Kikizo Games' John Carmack Q&A offers their Q&A about DOOM RPG for mobiles
and other topics. In response to their question about what's next, the id
Software Technical Director's brief reply seems to indicate that for the first time
since Quake in 1996, their next project will not be based on one of their
previous games:
We are working internally on a completely new project, but
we haven't made any firm plans yet for the future of the Wolf, Doom and Quake
franchises.