I've just recently started playing first person shooters and without a doubt OFP is the BEST at simulating combat. However, the MEDIC nd WOUND engine could stand a dramatic improvement. some of the previous suggestions mirror my own. Items that are key to this are:
1. Weapons fired in combat just aren't that accurate. Less hits and less accuracy.
2. WOUNDS are about 5 times more likely to happen than deaths.
3. Wounds vary in severity. Some wounds may not do much any harm at all while others may incapicitate you. What I'd like to see is much more debilitating wounds and less "hit and die" effects.
4. As mentioned, medics should have the ability to dramatically improve your chances of survival. Even if you are left with nothing but the ability to crawl on one arm and leg, a medic should not "heal" you.
5. Many more wound types. i.e. lose vision, lose hearing, lose limbs.
6. As mentioned buddies have to have the ability to carry or drag you. Weather or not the will is combat dependant. If shot, will your buddies risk getting hit to drag you to safety?
7. Uncontrolled screams and groaning. It happens. It might be nice to know that the recon by fire you laid down actually hit someone. Guys hiding might tend to be a bit quite, but when hit, they might just scream their bloody guts out. (litterally) ;)
8. Blood trails.
No doubt there will be lots of good ideas for AI improvements and even better handling of picking up items, but overall the whole combat/wound/medic engine rework would make OFP2 stand out above the rest....again.