My opinion... the action scenes in the new Superman movie Man of Steel show that a live action anime with fight scenes is possible, that the technology exists now.
Dragon Ball Z was the anime I watched most of the time when I was growing up. So I'd personally like to see a Dragon Ball movie that stays close to the original story.
While I haven't seen the Dragon Ball Evolution movie yet, some reviews complained about Goku being turned into a clone of Peter Parker (complete with school scenes) and how too many other changes were made.
So if a Dragon Ball or Dragon Ball Z live action movie could be made that stays reasonably close to the story, has good fight scenes, and keeps the animal characters too (Puar, Korin, Shenron, etc.), that could be something to get excited about.
I don't remember ever seeing Thundercats or Robotech while growing up. Some of those shows may be a little before my time. I'm curious now and will probably look it up later. If it's the action-packed kind of anime, complete with fight scenes, that would be interesting to see in a live action format.