wargame combat simulatio: what factors are most important?

Weapon, Sights etc, Cover, Range + Training; these should all combine together for a to hit roll.
it seems a lot, but the weapon would be for checking the range, and then maybe a chart, or a simple modifier to hit for range.
the training would provide the basis for a roll, higher trained more likely you are to hit, added to this would be any bonuses for sights [telescopic etc], and penalties from the above range and if the target is behind cover.

i see where our coming from on the ''incoming fire'' bit, but as oposed to making someone less accurate, would probably be more likely to just keep their heads down, or be behind cover?
same goes for morale; if a unit is Gung-Ho they'll do whatever, whenever, but if they're de-moralised, theyre more likely to flee, or just cower in a ditch somewhere...

hope i was of some hope!

I think you may want to be more specific about what sort of combat you're talking about here. Is this modern, and trying to be an accurate simulation of 2005/6 tactical engagements?

If so, drop the armor part of the equation. A soldier hit with a modern weapon is out of the battle. Living, maybe, but almost certainly injured, and injured soldiers are very rarely in fighting condition.

Also, the "toughness" of soldiers isn't a factor once hit. Any modern battle rifle will take out a soldier with a single hit, almost without regard to location or severity. A "glancing" hit with an AK-47, for instance, typically gouges out baseball sized holes, according to an aquaintance of mine who tended gang members in LA as a paramed.

Training is best reflected in resisting the degrading effects of combat on morale, awareness, and ability to coordinate and maintain cohesion. Most weapons fire should be a matter of massed exchanges, and once entered, a firefight should be very difficult to disengage from.

I've got lots more thinking on the subject, but I'll save it until I know if it's relevant or not.

I suggest you to read "the art of war" from Sun Tsu especially if you want to go in the details. Even if you are making a modern warfare game, some laws of Sun Tsu are still applicable.

May I suggest "How to Make War", by James F. Dunnigan? I've got the second or third edition, from 1988. It's dated now, in that it references Russia as an adversary, and mentions West Germany, but the facts obout the equipment and tactics haven't changed much, even if "new army" rhetoric has.

Edit: Ah, the fourth edition is out!

http://www.amazon.com/gp/product/006009012X/qid=1133657393/sr=2-1/ref=pd_bbs_b_2_1/102-6957221-0269700?s=books&v=glance&n=283155