Hell, I can't say with 100% certainty that we've even seen the last of Worf. That's how much that guy has played that part. He's not lucky to have been able to do it. The character was pretty popular. He was lucky that it didn't get awfully stale. He had his ups & downs, but I never got sick of him in the way I got sick of Riker or even Q after a while
Didn't Dorn get permanent scarring and allergic reactions to wearing the synthetics all those years? Unless he somehow acquires the Augment virus and looks human, I don't think we'll be seeing much of Worf again.