1. Bring back the call signs and emblemsthat were in MW2. this was one of the best things about MW2. they were all creative not like the emblems I have seen in Call of Duty Black Ops. I was disappointed in the custom emblem creator in Black Ops because it was so hard to make a good one.
2.bring back online split screen like Black Ops but this time make it like fifa 11 where only one person needs xbox live to play and the other one does not need it. Call of Duty has fantastic co-op options already, but the online split screen was an excellent addition in Black Ops. I used it all the time with my friends.
3. Bring back wager matches. Wager matches were one one my favorite part about Call of Duty Black Ops. They should have a game mode that is all about throwing knives. An all sniper mode would also be welcomed.
4. Have better security online . Hackers ruined MW2 at times. it was very annoying to have the game stopped every time the host left.
5. Add in a vehicle map. Vehicles haven’t always done great in Call of Duty, but it would be nice if they had 1 map that included some type of vehicle in MW3
6. Keep a wide variety of kill streaks. CoD is all about the kill streaks and I hope they have a huge list of them like they did in MW2. The nuke was kind of annoying but it encouraged you to play one and on until you get it which was fun. I think if they disallow tactical insertions in free-for-all that the nuke could possibly be brought back.
7.Add an x-ray vision perk that lets the player see through walls. This would be a pretty nice tool when looking for campers.
8.Add a couple ways to add flair when killing someone who doesn’t suspect it. Halo Reach had assassinations, a few move in CoD would work especially well with provoking opposing teams in killcams and final killcams.