1) Sniping should be like it was in COD4. Not broken like Black Ops, and no quick-scoping like MW2. Quick-scoping doesn't even really bother me. I mostly play objective based game modes and I've never come across quick-scopers that can take control of the game. They always get wrecked because they're trying to make their kills look cool, and most ultimately end up switching classes or just doing terrible. I don't mind quick-scoping, but I think if sniping was like it was in COD4, it would be a nice balance.
2) One Man Army/Danger Close/Noobtubes needs to be gone. This just seems like common sense to me. The game shouldn't be played that way, period. Anything similar to this should be done away with and prevented in future games as well.
3) Kills earned by your killstreak rewards shouldn't count towards other killstreaks. For example, Harrier kills shouldn't count towards a Chopper Gunner; you should have to earn those four kills yourself. I liked that they changed that in Black Ops, and I think MW2 multiplayer is too killstreak reward-based.
4) Take care of glitches, bugs, or any problems like that quickly, but also do it thoroughly. Staying on top of that kind of thing really makes the game more enjoyable, and shows you actually care about the state of your online game. This is going to be a big game, so take good care of it.
I think this list sounds pretty fair. If you agree, or disagree, let me know.