I would just like to mention how Planetside back in 2003 was so far ahead of its time and then so horribly mananged by SOE, where MMOs go to die.
Planetside had no 'out gearing' it was a progression for your ability to handel more than one type of situation rather than make it easier to kill someone. A brand new level one who knew the game could pwn hrd with almost any equipment there was in the game.
Of coruse lack of sanity checks resulted in warping which with the lack of development, air farming of ground forces, stupid respawn timers and other stuff which was plain wrong and never got fixed made people leave and not come back.
Oh yeah and one other thing. BFRs were the most BADLY IMPLEMENTED THING I HAVE EVER SEEN IN A GAME. I DO NOT KNOW HOW A GAME DEVELOPER CAN BE SO SO STUPID. Your a developer for a game where a majority think that in order to be 'compeative' you need to have the biggest best equipment (warping + HA cert + third person camera). And you give them massive robots that can pwn ANYTHING ELSE IN THE GAME ALONE. What do you THINK is going to happen? Idiots. - Slight Rant, Anyway...
Planetside used client side in a lot of things which meant it could have 500 players in one battle easily (the servers would really start to lag at about a thousand bit it did work).
No game I've seen has even come close to what Planetside did (note that Battleground Europe has a MUCH lower drawn player limit, originaly only 64, and is a crap 'game', its a pretty good 'sim' though).
Also, headshots are bad in this kind of enviroment btw and in general are luck not skill based. So in this case they actually got it right.