That was a great finale to the most satisfying Star Wars prequel we've gotten so far. Yeah, there's things to quibble with here or there, but at the end of the day it tied up all the loose ends the series had efficiently with solid emotional payoffs. Series finales are rarely this good, all things considered, even when they don't also have to work around a bunch of established canon.
There were dumb things in every episode, but all and all I really love this series. It seemed to flesh out the characters of the original trilogy, without causing any serious continuity issues, while also making the prequel trilogy feel more meaningfully connected to the original.
On the whole it was possibly my favorite Star Wars thing outside of the original trilogy, and definitely my favorite addition to the core "Skywalker Saga" narrative.
My one big problem with it is that Obi-wan had the beating of Vader, again, and walked away leaving him alive, again. Given that he is (as far as he knows) one of only two Jedi masters left alive, and given that Vader represents a huge danger both to the galaxy as a whole and to Luke and Leia in particular, shouldn't he have finished the job?
No, but a line or two referencing the consequence of that decision and the reasoning probably would have made it seem less irresponsible. I can accept that Kenobi can't bring himself to kill even the husk that once was Anakin, who was basically a brother, a son, and a best friend all wrapped up into one for him, and I think McGreggor's acting and what we know of the relationship almost tells that story and explains that decision well enough, but an actual line spelling it out a bit more might have been good. I think not explaining and letting the audience ponder could be better with comparable characters in a different series, but given that everyone knows he couldn't kill Vader here for continuity reasons, the character reasoning probably should have been spelled out better so it doesn't seem like an overly convenient decision.
That said the dialogue between Vader and Kenobi here was excellent as is, and I'd hesitate to change any of it.