And Activision owns the brand, and the game engine. Zambella and West have non-competition clauses, if they lure IW employees over they will get their asses handed to them by the judge.
Respawn will no doubt create some form of FPS, eventually, and it might be good, but IMO there is not alot I can see them do that hasn't already been done.
infinity ward could not make a good FPS game if their lives depended on it. they suck!!