probably the only two things I don't like are how easy it is to run yourself over after getting out of a vehicle and how you can run over your teammates going 1mph
edit: well, i was mad about those two things because i keep killing myself getting out of cars, but i also hate the whole lock-on system with planes. i can lead my shots way better than the stupid lock-on system, there should be a way to switch between the two, that way you could like get a lock on a guy and make him go the directions you want so its easier to aim ahead with your missiles.
also the fact that the anti air SUCKS. for instance, in Oman, there's only ONE anti air at the MEC main base, and the USMC can usually be over at the MEC base (because they typically spawn closer) if they fly higher in the thinner air with after burners all the way and bomb the MEC jets as they're taking off, then keep them down the entire game while killing the anti-air gun periodically. basically they took out the SKILL of shooting down planes by leading with stingers in DC. That leads to the next thing I hate, the overall skill level BF2 takes is much less than DC. The guns are worse, the lock-on system is lame and sucky. I can shoot down a chopper with an RPG in DC in one shot by predicting where it's going, but not in BF2 due to the crappy lock-on system (with stingers/igla, not anti-air kit which is too slow to hit any air). They just throw flares out and avoid the rocket. That takes all the skill away. The guns are totally inaccurate though some would argue with me (not saying this because I'm bad with them because im not).
Tanks and cars burn to death when at low health = LAME. Then there's another second explosion with the wreckage. WTF is that? Why should the wreckage explode again? If you're hiding near it it kills you with the second explosion.
Helicopter controls are totally not-fun however "realistic" they may be. If I can't aim my nose down to shoot at something without coming 10 feet from the ground, what's the point of the pilot having rockets anyway?
No more guided missile launch sites, why did they take this out?
Artillery is so lame, click a button and get 6 free kills. W00T! so much skill involved there! Bring back the normal DC arty where you actually had to LEARN how to use it.
Actually, the whole commander mode is retarded IMO. sure it adds a different strategic twist to it, but I think it's better for the players to make each other aware of nearby enemies and to shoot arty or give supplies.
The game basically invites base camping as you have to enter the enemy main base to blow up their commander buildings. I don't know about you, but I don't think base camping is a very fun part of the game.
The planes are ridiculously fast. Even if there were anti-air missiles you could aim by yourself there would be no way to hit a jet going that fast.
C4 glitches whenever you try to switch to the detonation button and won't switch, but instead throws another c4 out if you try to press the detonate button while its "trying" to switch.
Grenade launchers are unbalanced. There should only be 2 or 3 shots in it, not a ridiculous 5. They're so easy to base camp with.
I know none of this will probably be fixed aside from glitches like the C4. This guy in my friend's clan knows the head guy in charge of BF2 (forgot his name, its Steve something.) Apparantly they're pretty good friends, and he brought up all these issues and more to Steve and basically he said "I don't care, I gave them the game I wanted to give them. I'll leave it to the modding community." EA sucks.
Don't get me wrong though. I love the game and think it is very fun
edit: woops that guys name was Scott not Steve, Scott Evans actually after I googled it.