What bothered me the most is that PS2 was just such a vehicle fest. The costs and cooldowns were way too low and everyone was spamming tanks and shit. There was no infantry battles whatsoever except for Crown and Biolab. Doubt that changed.
Actually this changed a lot. A river of infantry tears soon turned into vehicle (and especially air) blood. ESF are like paper now and rockets hardly do anything to infantry unless it's a direct hit. I seldom get killed by tanks or aircraft (not like I did much when they were supposedly OP either). At some point lock-on launchers were so ridiculous I suspect half the air players just GTX, but now only TR keep on using them frequently because we have a lock-on 5-shot launcher that can lock on air and armor. All in all it's quite balanced now and lock-ons are getting another nerf in an upcoming patch so it's going to be even better soon.
They also added a few gameplay possibilities, with SMGs and the fact that infiltators can use them, very powerful but hard to use pump action shotguns, large caliber sidearms, new (much better) MAX anti-armor weapons, time-limited missions with rewards, buggies...
The problem remains that too many battles are completely one-sided though, because even large bases are still too hard to defend, while small stations are simply worthless. Also, the derp waiting when you already won a base attack is just derp.
The game is badly optimised for AMD CPUs (like quite a few games might I add, developpers just seem to forget about those), but most ATI and Nvidia single GPUs work nicely enough. The game is very CPU intensive and doesn't scale well. Even with a beastly CPU you won't get great FPS in battles with hundreds of players.
About performance, PlanetSide 2 has weird settings, lower quality textures in fact decreasing performance and whatnot. There are a few very good, if not slightly old guides around, just google planetside 2 performance.