The 32X port of Doom wasn't all that bad. I tested some of those Doom 32X prototypes that were found by drx and the oldest two alphas (they were from around September 1994) actually had the game full screen. The game was fairly complete from what I saw (the first two levels were completely playable), there was no sfx yet (though in the second oldest one there was a very basic version of the Doom music, nothing else), but the frame rate was really sluggish once you approached a lot of enemies. This has to tell you either they couldnt speed it up, or Doom 32X was rushed like many other 32X games.
Still, it's a good port, and definitely better than the SNES version (save the music).
Wolfenstein on the Genesis is possible. It wouldn't look that pretty, but possible nonetheless (thinks of that Duke 3D port from Tec Toy :P).
Perhaps the SVP chip could've made for a good Genesis port of Wolfenstein.