I’m actually really worried about the hints of a pre-ANH Vader vs Obi Wan rematch. Many people seem to have conveniently forgotten the line “when I left you, I was but the learner; now I am the master”. A duel between them would be the definition of breaking the canon for fan service.
That line was vague though. He didn’t say “When I left you, I was burning next to a pit of lava while screaming about how much I hate you.” There were no direct lines about what exactly their last confrontation was, so there could potentially be room for another duel in between there.
My comment about hoping they do it in a way that makes sense was mostly just directed at character development. If they can flesh out the characters, maybe explaining their attitudes in the OT as well, that would be great. But if it’s just a duel for a duel’s sake, that’s no good.