Maybe a merge with Valve. So they will become the platform to build and to sell the games. They will have all the developers and resources on the game development world.
Doubtful. Valve has Source, their own game engine which their entire game portfolio is built on in one form or another. While rare it has been occasionally licensed out to other developers. Merging with Valve with two different competing big budget engines to maintain and improve. I just don't see how a merger could benefit either company.