Obviously he can't kill Obi-Wan for plot reasons, and it's for entertainment so bring in a four-saber villain even if he gets little action (he probably saw Maul and Boba, mysterious and very popular, left people wanting more) but is GL teasing us?
Can anyone think of a reason he doesn't just swing away with the other two sabers, or one? Honor, Jedi style? Is it just pride... he did show that. Or should this shot not exist? Sorry if it's a bit bright, but it's the apex.
Anyway... just bring in Obi-Wan with the clones to smash them, IMO, and they have a duel in the chaos like Jango and Mace sort of/would have had, if his jetpack worked.
Damn the slow kill. There's a war, great warriors, let them fight and heck troops can make some difference. GL definitely put his 1930s into the movies as he said! Invincible good guys, slow (non)kills/cliffhangers, etc.