I'm going to focus solely on multiplayer here.
- Fix the bugs. Obvious one really, actually have a public beta test so glitches can be weeded out before release and avoid weeks of Unlimited Care Package glitching.
- Bring back Dedicated Servers on PC version. There is no reason to take them away - there are so many hackers on the PC version; I ran into more in one week than my entire time playing TF2. The lag is pathetic as well - if you have a 'three bar' connection you have somewhere between 100 and 200 ping. Ridiculous.
- Remove the following perks:
Stopping Power, Danger Close, One Man Army, Commando, Last Stand.
Stopping Power isn't annoying or anything, I just think that you are pretty much forced to use it because everyone else is going to use it. Danger Close and One Man Army is a very overpowered combination that needs to be removed. Commando is just dumb that you can lunge from three metres away.
Last Stand is the worst perk in the game. People I shoot with a Sniper should not be able to deny me a kill by equipping Last Stand, then killing themselves with a stun grenade after I've shot them. Shooting someone point-blank with a SPAS-12, only for them to go into Last Stand and knife me in the shins is total bullshit.
- Remove the grenade launchers. They're cheap as hell, especially with One Man Army and Danger Close.
- Shotguns should be Primary weapons, not Secondary weapons. Secondaries should be restricted to Handguns and Anti-vehicle launchers.
- Remove Care Packages, Emergency Airdrops and Predator Missiles. The first two are bullshit because of the randomness; you should not get a Chopper Gunner for four kills. Predator Missiles are cheap as hell - at any time one could appear above your head and you have no defense for it.
- Balance the weapons more. Overall, Light Machine Guns need a buff, Assault Rifles a nerf. Some guns are so vastly inferior to their counterparts it's laughable (F2000, anyone?)
- Remove Tactical Insertions. Nuke Boosting sucks.
- Killstreaks should not count towarads your streak. 5 Kills should not get you an AC-130; 7 kills should not get you a Tactical Nuke.
- Remove Deathstreaks. I don't need to explain this.