ILM digital magic and prosthetics can work wonders.
If memory serves, the bad guy in the book after "Return of the Jedi" (Volume VII???) is physically unimposing, with blue-green skin. "Grand Admiral Thrawn" was his name.
Who knows what Disney will do to the franchise, though. IIRC, a couple of characters in the final trilogy were interesting, but the stories were pretty bad. We will see what Disney bases the next movies on.