NOTE - this applies to the period when the '(Main) Battle Tank' dominated warfare, essentially from the Second World War up to and including the first Gulf War (i.e. from the start of Blitzkrieg up to the point before the mass introduction of GPS guided weapons resulted in air-power totally dominating the battlefield)
What's wrong with the existing system ?
Almost everything - starting with the 'six man' units and combat consisting of 'hits', 'evades', 'wedging' and 'blocking' = all of which might make (some) sense in the world of 'Ancient Warfare' table-top toy soldiers (i.e. prior to the mass introduction of gunpowder weapons) but results in total nonsense when applied to any sort of attempt to simulate 'realistic' armoured warfare !
Whilst the minimum Infantry unit would be the 'Platoon' (in the modern Army this would consist of at least 28 individuals - during WWII it consisted of 40-50 men), the minimum 'organisational' unit would be the Battalion (800+ men). Other typical 'organisational units' would be Armoured Regiments (approx 80 Tanks) and Artillery Regiments (light AA / anti-tank = 40 to 50 guns, 'Heavy' Artillery = 24 guns (plus approx 600 men)).
Further there would be many supporting components (men, vehicles, ammunition), casualties to any of which would reduce the effectiveness of the whole unit without 'killing' the actual Tanks or Guns (and the existence of which is why a 'flank' or 'rear' attack can be so effective)
So whilst an individual Tank (or gun) might 'miss' and an infantryman might even 'evade' a single shot, when two Armoured Regiments clash casualties will be inflicted and suffered on both sides, 'no matter what'.
How will the new system work ?
First, the '6 man unit' (which limits casualties to steps of 1/6th) will be replaced. Since every unit actually consists of multiple individual elements (dozens of tanks, guns, vehicles & hundreds of men) they will start at "100%" strength. This allows damage (casualties) to be taken in 1% steps. The whole nonsense concept of 'hits' and 'misses' will be dropped - combat outcomes will depend mainly on attack & defense 'strength' (which will take into account the number and type of unit on each side with adjustments for the effects of terrian - for example, Tanks are rather more vulnerable when facing infantry in the middle of a wood, whilst the infanty are going to suffer when facing Tanks across an open field) plus some 'small'** random factor.
**The random factors will form a 'normal distribution' with a standard deviation of .25 from the 'average'. The random factor will be asymmetrically adjusted by the unit experience ('raw recruits' are more likely to perform unexpectedly well (from a low base effectiveness) and 'veterans' unexpectedly badly (from a high base value) - whilst the 'average' battle hardened unit may go either way from an average base effectiveness)
'Experience' does not result in a linear increase in effectiveness - 'green' units rapidly become 'battle hardened' (or dead) but it takes much longer for the 'battle hardened' to become 'veterans' - after which very little increase in effectiveness is seen. Units that are 'damaged' and 'repaired' (i.e. take on new recruits) will loose some of their effectiveness, but will improve much faster (as the remaining experienced troops / veterans pass on their knowledge 'by example') than those units starting with 100% 'raw recruits' (who become more effective by 'trial & error' (and the weeding out of the idiots who would otherwise doom the entire unit)
Effectiveness applies to both 'defensive' and 'offensive' capability, with 'raw recruits' typically being poorer at defense (most of their training will have focused on offense). The 'battle hardened', on the other hand, will become defense 'experts' (or at least those who survive will) and veterans experts at both defense and offense.
Further, as units take damage, their combat effectiveness is NOT reduced in a balanced or 'linear' manor. Offensive capability is reduced a lot faster than defensive - a unit at 66% strength is likely to be reduced well below 66% offensive capability whilst (those still alive) may actually have INCREASED their defensive capability ... and by the time a unit reaches 33% strength, chances are, if they are not running away, they will almost certainly be hiding in fox holes or bunkers (so much higher defensive capability) and are likely to refuse (or at least avoid initiating) any attack at all (so minimal offensive capability). Remember - damage is much more likley to the larger equipment (Tanks and Artillery can't duck or hide in a fox hole) than the actual men
In 'modern' warfare, terrain plays a relatively minor role, mainly on movement (and 'line of sight') rather than combat.
Of course, defending** units can dig fox holes and better conceal themselves in some types of terrain than others. Further, terrain such as as forests & mountain caves etc. can give defenders some real protection, especially against ranged fire & air attack. Needless to say, any vehicles (and especially Tanks) in a wood are very vulnerable to infantry (who can sneak up and 'bazooka' them) whilst only suicidal infantry would attack Tanks across an open field. Finally, those defending 'obstacles' (such as rivers, tank traps etc) will receive fewer casualties as the attackers struggle to get across (which will reduce the effectiveness of their fire at the enemy)
**Attackers plainly have to give up any concealment offered by terrain, so will not benefit from 'cover'
When multiple units attack a single unit, the defenders will have to split their fire but the more experienced will typically direct it proportionally more against the enemy they are most effective against - so the 'weaker' attacker is likely to take a higher portion (in relation to their strength) of the damage/casualties caused by defenders (Infantry attacked solely by tanks will fire 100% at the tanks .. and watch their bullets bounce off .... whilst those attacked by combined infantry and tanks should plainly direct most of their fire at the infantry whilst only those with anti-tank weapons focus on the tanks - unless, of course, the enemy tank commanders are silly enough to pop their heads out of their turrets :-) ). Needless to say, veterans will get this 'more right', whilst raw recruits are likely to continue to blaze away at the tanks to zero effect ... whilst taking casulties from the enemy infantry
Defenders with a ranged fire capability can be expected to 'open fire' on their attackers before contact .. however, when attackers are supported by their own ranged units, the defenders can be expected to take casualties before they have a chance to respond - and attackers 'moving to contact' will be too busy moving to use their own ranged capability. This means, for example, that air units moving into contact with (ranged) anti-air will take casualties (on the approach) as well as when 'in contact'
The current movement system does not allow air units to move over any other unit (not even their own sides units) - this nonsense will be corrected (air units will still have to end their turn on an empty hex).
Bombers and ground-attack aircraft will be 'assumed' to attack any enemy unit they fly over - but they will also be vulnerable to all enemy anti-air they pass within range of (which will fire at them automatically)
The same 'automatic fire' will be applied to ranged units of both sides in combat. During a players own turn, they may direct their ranged units to fire on chosen target, however any not so direct will be assugned to fire automatically in support of their own sides nearest forces (see at end below). During the other players turn, all your own ranged units will fire automatically in support of your own forces being attacked that turn (if there are none, your ranged units will fire on the nearest enemy)
Aircraft and anti-aircraft guns
AA missiles are separate units and are dealt with as a separate subject. The focus here is on anti-aircraft guns
Anti-aircraft guns are split into 2 types - short range (2 hex) and 'long' (1-3 hex) range. Both types are 'dual purpose' (i.e. can also attack (or defend against) non-air units), however against non-air targets, short range AA has a 1 hex range (i.e. no 'indirect' fire capability) whilst long range AA gets a +2 (so 1-5 hex).
Short range anti-air can only 'attack' aircraft that has 'descended' to attack them or their friends (the High Level Bomber attacks without descending, so is 'immune' to short range anti-air).
Conversely, long range anti-air can only 'attack' aircraft that has NOT descended to attack them or their friends (this means High Level Bombers are always vulnerable to long-range AA, as are all aircraft not actually in contact with the enemy and attacking them)
What is the new combat sequence ?
Air to ground and ranged attack is applied first (and casualties taken) before combat between units in contact is resolved. Units starting the turn in contact with the enemy can not use their own ranged attack capability (but they may still be a 'target' for enemy ranged attack)
A1. The attackers ranged attack (which includes air-to-ground and supporting artillery) is applied against defenders and defenders losses subtracted from their strength. Defender gets terrain ('cover') advantage. Experience level of ranged attackers is increased depending on effectiveness of their attack
The attacker (player whose turn it is) gets an obvious advantage in that the defenders losses are subtracted before they get a chance to return fire, however the 'disadvantage' is that any attacking unit with a 'ranged attack' is much less effective (so you should avoid moving your AA and AntiTank guns into contact !).
A2. Defenders ranged counter-attack (including any supporting artillery) is applied against the (direct) attackers (in range) and attacker losses subtracted.
Defenders ranged fire is divided among multiple attackers in range in proportion to the effectiveness against that attacker (adjusted by the units experience level) with a higher proportion of a defending units fire being aimed at the enemy most direct to it's front. Casualties are adjusted by the targets numerical strength (a target at 100% strength has twice the 'density' compared to one at 50%)
Experience level of the ranged unit is increased depending on their own effectiveness
The defenders 'indirect' fire will be a lot more effective (as they are not moving), however there will be fewer surviving (after step A1) to deliver that fire
A3. The 'all units in contact' combat phase. This is complicated by the fact that a player with units still 'in contact' (from a previous turn) may choose to 'do nothing' (i.e. 'defend only'), however two units 'defending' against one-other will still take some casualties. The player may also choose to re-direct a units 'attack' to (any) enemy unit in contact (which may mean attacking an enemy unit not at it's front - the players unit will then turn to face the enemy chosen as the attack target).
Choosing not to attack means lower casualties (as the units defense is increased), however facing is important (because not only is a greater portion of the units 'attack' value allocated against the enemy to it's front but a unit's defense value is reduced when attacked in the flank, rear flank or rear). Further, to gain maximum (or some) advantage from (eg) defending a river crossing, the units front (or front flank) must be facing the enemy advancing across the river (i.e. from the 'disadvantaged' terrain).
A player may thus decide that a unit initially attacked (say) to the front by a strong enemy and in the rear by a weaker one, should turn and attack the weaker (in an attempt to 'break out') ... alternatively, faced by a frontal attack by a weak unit and from the rear by a stronger one, the player may decide to turn it's unit to face the greater threat
Each unit is checked for 'enemy in contact'. That units 'attack' power is then divided against the enemy units and the casualties caused recorded. The units experience level is then increased (depending on their effectiveness)
The division of a units attack power depends on multiple factors. If the player has directed an attack, most of the power will assigned against the selected target, however if the unit is being attacked (ie is in contact with) other enemy units, at least some of it's power will be directed against those instead, as follows :-.
Default allocation is 17.5% against each front flank, 10% against each rear flank, 5% against the rear, with the remaining (which will be at least 40%) to the front. The 'attack bonus' is then applied (by multiplying up the frontal attack value)
If the player has not directed an attack (either it's the other players turn, or they are 'defending only') a unit surrounded on all 6 sides will allocate it's power equally against each enemy it is in contact with. Note that only defending units gain a 'terrain advantage' (see defense, below) and only attackers a 'terrain disadvantage'
In both the above the %allocation will be modified by the units experience (so that more power is allocated against an enemy unit it is more effective against) and then by their current strength. Note that the more reduced in strength the unit is, the more the attack allocations will tend to be 'equalised out' (i.e. the closer an 'attacking' unit will become to acting in a 'defensive only' mode)
Finally the attack value is multiplied by the units effectiveness against that target.
After the attack% value is calculated, a defensive% value is worked out. The attack % is then divided by the defensive % and the result multiplied by a random value adjusted for a units experience. The modified result is subtracted from the defending units strength and added to the attackers experience value
The defence value starts with the effectiveness of the defender in defending against that type of attacker. This is then modified by any 'terrain advantage' value and by the defending units experience. The defense value is then INCREASED by a value based on the number of casualties the unit has suffered (the rational here being that after each combat, the survivors are better at defending = i.e. avoiding getting killed). Finally, if the defender is 'not attacking' on this turn, it's defense value is further boosted.
The intent is that a typical battle between two similar units with no other factors applying, will result in 10% casualties for the defender, 15% for the attacker.
The 'random' multiplier will be between 0 and 2 (centered on 1.0) with a standard-deviation of .25 (so, 50% of the time the random value will be between 0.75 and 1.25). If the result is greater than 1.25 (defender about to suffer increased casulties) it is reduced by the attackers experience (the more experienced the attackers, the less likly they will suddenly perform better), if less than .75 (attacker about to recieve fewer casulties) it will be increased by the attackers experience (the more experience the troops, the less likley they are to perform worse than expected)
A4. Finally, units now below 0% strength are removed.
Note that 'support' is gained only from friends with ranged attack capability - i.e. the 'blocking' and 'wedging' nonsense has been replaced with 'real world' effects
How is automatic artillery fire allocated ?
A1. Whilst the player whose turn it is (the attacker) has the chance to 'direct' his artillery fire, the 'defender' does not. So the defenders 'counter-fire' (and any of the attackers artillery that is not 'directed' by the player) will be allocated against enemy it is effective against as follows :-
1) If in contact with the enemy (which includes air attack), no indirect fire is possible (the gunners are either resisting a ground attack or sheltering from air attack).
2) If under (indirect) fire from enemy unit(s), this unit directs it's own fire at those enemy (in range)
3) Else the unit will support all friends attacking enemy (in range)
4) Else the unit will target any/all enemy directly next to any enemy in contact with friends (in range)
5) Else the unit will target any/all 'priority**' enemy in range, else any in-range (against which it is effective)
Ranged units won't automatically fire on enemy that is directly in contact with friends (4 is firing on the enemy 'supporting' units) - it's assumed that during combat the enemy units are too 'mixed up' with friends to be reliably targeted. However a player may direct his own Artillery etc. to bombard enemy units in contact with his own (in which case his own units will take some casualties)