Ok, hear me out...
Attacks should have a distance meter.
If you get attacked with an axe, it doesn't make sense to hit that person with an Anti Tank, that would have both players blow up. I always try to imagine how the fights look, and imagining someone hitting you with an axe first, and then that person turns around and fires off a grenade shell from an anti tank?...that doesn't make any more sense than the opposite, a person firing at you with an anti tank, and then the other person magically hits you with an axe in the face on their next move. In the first scenario the attack starts up close with an axe in the back, in the second someone shoots at you from a position pretty far away.
By introducing short, medium and long distance to target you could get much more realistic fighting scenarios, with different weapons working best at a given distance.
Temporary weapon example:
Throwing a grenade should be done from medium range, but hitting someone with pepper spray should be done from short distance. Aiming at someone with pepper spray from a distance should just be a waste, and throwing a grenade at someone close to you should inflict self harm as well as harm to opponent.
Your turn, move or stay
As part of your turn you could move distance after each weapon use, getting closer or further away from target or staying where you are.
Get shot at, shoot back, move closer while getting shot at again, stab with your macana, get stunned with a cattle prod, see opponent move away twice while shooting, shoot back with your M4A1. Realistic to imagine, and would diversify the ways of using different weapons, apart from just looking at their stats. Might make Speed a more important stat out of the 4 as well.
Kamikaze
Heck, you could even blow yourself up if you're getting pounded by a baseball bat, maybe making a double KO a new type of stalemate-like scenario.
Automated Defense Moves
This could be an automated function on defenses just like percentage settings for what weapons to use already is, with button options like "Always move away from target" for the sniper style player, and opposite for the close combat style players.
Weapon ranges
Most melee weapons would be used on short range, naturally, weapons like a pistol could work well on more than one distance, both on short and medium range. Most rifles could be long to medium range, but some could be clunky to fire even at medium range, like the Heckler & Koch with bipod mod mounted (or an Anti Tank once again).
Would this be a terrible update to get used to at first?...100%, guaranteed! I just like swinging my Dual Hammers around, and will usually keep doing that no matter what the opponent is up to. I'd have to stop that altogether.
Would I find it more realistic, and eventually like it, just like Crimes 2.0?...Again, 100%, guaranteed!
Ferrik