Sure it will be fun, but won’t lie, am least enthused about the idea of an Obi-Wan/Vader rematch. There’s a clear implication in the movies that the Jedi are thought extinct, therefore that Vader assumed Obi-Wan was dead. Him finding out he’s alive after Order 66 means he has to ‘fake’ his death again.
Not a fan of tinkering with the mythology for fan service. Would prefer Inquisitors hunting Jedi found Obi-Wan but that he kills him before he can report back. You still get the Jedi action without messing with the story too much.
All valid points and I’ve been wondering as well how will another encounter between them fit in appropriately with the established narrative. It’s quite ambiguous though with their dialogue in ANH (“we meet again at last” for example, how long a period of time that is, I don’t know).
“When I left you I was but the learner” however to me clearly refers to their duel. That might be a troublesome point to overcome
Obi-Wan didn’t fake his death however in ROTS, he was last seen walking away from Anakin on Mustafar. So not sure that Vader would have assumed he was dead, he was the last person to see him (albeit Obi-Wan wouldn’t have left him alive if he thought Anakin would survive).
Overall though, one of biggest problems I’ve had is how Obi-Wan and Yoda just excuse themselves and sit on the bench after ROTS as the Empire rules the galaxy. Being in a position to do something about it, but not doing so. In that respect, I’m intrigued to see what/how/if they did try again to defeat the Sith during that very long (and largely unexplored) 20 year gap between episode 3 and 4.