Villains don't have to be exactly as they were originally intended. Take Freeze for example. They could just take his theme or Revenge and wanting to save his wife, he doesn't have to turn blue and start using a Freeze gun. He could just be working in cryogenics and be involved with the wrong people in desperation to help his wife.
I don't think that Mr. Freeze would have to be changed to that degree. Nolan has been very good at giving us a world that looks fairly grounded while keeping the characters true to the source material. Look at how he managed to give us Two-Face with the half-and-half-suit and a face that looked exactly the way it does in the comics, and none of it looked out of place. It wouldn't surprise me if there was a way to do Mr. Freeze along the same lines, cryo suit, freeze gun and all.