Prone doesn't work in games with map design such as Crysis 2.
Now, Crysis 2 has similar maps to MW2. Except with verticality. And balance. And variety. And beauty. And competence.
Moving on.
So, in MW2 and Crysis Wars, even, proning had 2 major flaws:
-Instant faceplants which take 0.5 seconds, gaining accuracy as you fall, landing directly on your nose, but you retain perfect accuracy
-More camping. Particularly in long grass.
Finally, Right now, not a lot of people snipe. The majority use machine guns and run around. Putting prone will influence some people to start sniping. Which is a good thing because it brings more tactical diversity to the game.
AHAHHAHAHAHAH.
Sniping = camping = bad
So.... Nope!
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People are already camping even without prone so honestly camping is always going to happen no matter what, there will always be spots that people tend to camp that give better views of the battlefield.
There are so many ways to maneuver and so many ways to sneak up on people that even if you are sniping in prone position you wont be for long with the tracer option and the nanovision. Sure some maps are designed for close quarters combat but there are other maps like Statue and Sanctuary with enough open space to give people the option of going sniper.
The whole point is it gives more tactical options for evading line of sight and generally being a sneaky bastard, if you want a mindless pure fragfest play unreal tournament, tactical shooters should have options and should require actual thinking and skill to be a decent player.