Okay, didn't read thru all the posts but I'm all for Combined Arms and Multi-Theatre engagements so I'd say concentrate on the Mech but don't deny us non-Tin Can players the opportunity to take them down
I don't know about you but I think a co-op of FPSer's playing as infantry fighting to take down a mech would be horrifically painful/humorous/challenging and loads of fun(like an end-boss fight everytime --Pygmy/cockroach army vs Giant).
Thats one things I Didn't like about Mechwarrior games (no playing as Scout(non-mech or Mech Thief) archetypes or jump-infantry(sticky grapples + motorised tow/climbing cable + AV type explosives for the win -- good luck dodging) please add fire retardant infantry armor though PLEASE).
Let's not lose sight of the fact that this IS a mech game.
I am completely for all of the various supporting roles that have been discussed such as the shuttle pilot, research science, manufacturing, and more.
However, I do not want to see this game devolve into just another special ops game with bunches of Seal teams out there to take down the mechs. There are more than enough special ops and Swat team games already as far as I am concerned and NO viable mech games. This should be a game for those of us that are into mechs first.