The matchmaking and connectivity issues. Maybe addressing the size of hitbixes so the weak will not have it so easy this year ( I refuse to believe they are the same as every year). Address hit detection.
"All guns seemed to have Stopping Power in it which made each gun in the gun pretty powerful and equal. So it was a balanced system, since whatever weapon you used it would be powerful no matter what."
No sir. Making every weapon do extremely high damage isn't balancing, it's catering to those that can't win gun fights that don't end after 1-2 bullets.
Gun's also should not be equal. Each gun should offer something a bit different than the rest. One gun might do more damage, but have higher recoil. One gun might have 0 recoil, but do little damage. This is one thing i really couldn't stand about MW3, there wasn't much diversity in weapons especially since all weapons had proficiencies which pretty much make all weapons the same.
Bring knife lunges back to World at War distance.
Decrease how powerful stealth perks are.
Give shotguns unlimited range.
Increase hip-fire spread of assault rifles.
Decrease the recoil of LMG's.
Decrease mobility of assault rifles.
Keep weapon damage similar to BO.
Larger, more open maps.
Oh, and more semi-automatic battle rifles.
I would also like to add. Remove the redundant in-game friends list. We already have a SEN list that is working our PS3s to track friends, we do not need another for just one game filtering those who aren't playing the game and those who are. It lagged the system so bad last game, it caused freezes, and it was bad when you got a invite or a message.