there are a few on the way. I don't remember what they're called tho
It would never work. Closest thing will be FireFall which will have 100's of players for coop (pve). They haven't said anything about the mp but my guess is it will be smaller teams
lattice ruined planetside
(seriously it did)
I'm still waiting for someone to make some kind of giant sci-fi combined arms game with FPS planet battles and space sim/strategy combat that can exert influence over one another.