Hm, I'd rather compare BF2 with the BF1942-Desert Combat mod. Sure BF2 has all of the new goodies like the updated engine, graphics, physics, squads..etc. But in Desert Combat, you lived without all of that. The thing is, DC IMO seemed much more balanced-Kit wise. This is just my reminiscence/speculation:
-Engineers could take out tanks by sneaking up on them and tossing a mine or two directly onto the tank and it would most likely exlpode a few seconds later; (sometimes this was more effective than the AT kit) where as in BF2, the mine will usually just slide off.
-Assault class didn't seem like much of a problem with its GL attachment as it is in BF2.
-Support class actually has an accurate LMG, hell you can fire off 5-10 rounds or so in bursts and the crosshair would recenter to almost 0 recoil- making the class much more useful.
-Sniper Class has plenty of rounds for their primary sniper rifles, and...they're accurate!!
-Anti Tank class had no guided rocket feature to their weapon, which I kinda prefer rather than having to stay put to guide your rocket into something. AT also had portable Stinger missle launchers as well; (depending on map) If I can remember, you needed 1 stinger to down a small heli., 2 for attack helis. and maybe 3 for transport helis.
-Medic Class..well I can't really remember too well :P
-Spec Ops class didn't seem to be as powerfull as it is in BF2, (no sticky c4, or the precious G36C)
And other things: No pesky commander giving off your position while your camping as a sniper, etc. No team-seeking air-to-air missles, and IMO the flight physics for helis were a blast-you can strafe ground troops and other vehicles while maintaining high altitude in a constant circle. Artillery was provided by long range attack vehicles such as the SCUD! No flight altitude limit- as in losing control of your craft for flying too high :/ and much more.
But in the end, I'd rather play the current installment, however theres so much more room for improvement- EA/Dice needs to go back to their roots!! >;/