According to this article [url]http://kotaku.com/5619046/crysis-2-is-like-parkour-free running-with-guns[/url] when you get a kill in Crysis 2 MP you earn a dog-tag, which doesn't sound so special, but wait there is more...
and according to the new Limited edition trailer (right after the player throws a grenade), players may have to physically go and retrieve the dog-tag from a enemy player's body if they want to use things like radar sweep or other kill streak rewards.
This could be GREAT for gameplay as it forces ppl to move around if they want to get their rewards which should create a lot less of the camping for killstreaks you see in games like MW2.
None of this is confirmed, I'm just interpreting and anolyzing, but if there is a system similar to my theory in the game then we can expect a much more fun and less "campy" online experience.