So...
Luke ignites the saber, sees it works.
Vader emerges from the fog once again, ghost like, in slow motion.
Luke rises, raises his saber, and turns it off as Vader swings.
Just as Vader would make contact, slicing through Luke, he instead fades away, no more than a vision, now conquered.
In his hovel, Yoda smiles.
Eh?
The new Luke shots would all be from behind, thus making it possible to film them with someone who isn't 1983-Mark-Hamill. The Yoda shot... not sure about that.