WWII online did it way before Planetside people! Although the proportions were so close to reality that it was just as depressing travelling(walking) 20km to battle just to instantly get strafed by some asshat in a Stuka the moment you got there. The vehicle controls/weapon ballistics were complex as shit, putting simulators to shame. At least it felt as if there were some grander purpose for it...something I was unable to see in Planetside (that may/may not have been fixed with subsequent expansions & what have you).
I really hope this is NOT a Starcraft MMO. They promised so much for WoW originally and it'd be too much to see the Starcraft version go the same road, after much hype/impossible expectations as a result from said hype. Bring on Starcraft, the sequel or Diablo, the third!