I would love to see a well-done Castlevania adaptation. And I agree about Alucard. Much as I love the guy, angsty, brooding, misunderstood bishounen vampire anti-heroes have been done to death for over a decade now. Let's have a monster-hunting romp where vampires are monsters, end of story, and watch Belmont whip them all into oblivion. (marketing tagline: When a problem comes along...)
I didn't think the first Mortal Kombat was a horrible film: it used the Enter the Dragon underworld tournament plot, which as you implied is really the only way to handle a fighting game adaptation, the characterizations were pretty good, the soundtrack was awesome, and we got a couple of cool-looking fight scenes, what more did we want? It's not like the source material was deep to begin with. (The sequel, on the other hand...). And I consider the Dead or Alive film a guilty pleasure, probably because it doesn't take itself seriously.