It feels pretty clear to me that these six episodes serve as a far better prequel to Star Wars than the actual prequel film trilogy did. It's more grounded in characters (who don't behave woodenly), and it's more cognizant of trying to lead up to the original (as opposed to simply "rhyming" with it -- George Lucas' oft-cited term for repackaging his own earlier ideas). Of course, the paradox is that this series wouldn't hit as strongly had we not already seen Ewan McGregor play the role of Kenobi. I can't claim that this in any way supplants the prequel trilogy; it's just better.
Of course, it isn't without its flaws. Some of the character behavior is a little hard to square without just falling back on "people can be complicated and inconsistent." (True, but not usually a winning defense of fiction.) Increasingly in the later episodes, characters act in ways that don't seem to fit with the previous episodes -- instead, they're made to fit with what must be true because of where Star Wars begins. (To get slightly spoilery about the final episode: the theme of "mercy" seems big at the end, but not very organically incorporated.)
But there's a lot more good than bad in the series. There was surprising fun in seeing many actors return to Star Wars when you probably thought you'd seen them there for the last time. There was even more fun in seeing many things appear in live-action Star Wars for the first time (especially if you've watched the Star Wars cartoon series).
There were several compelling new characters that resonated with me despite limited screen time. Kumail Nanjiani and Indira Varma felt like especially strong additions to the Star Wars universe, and Moses Ingram did a good job as the Third Sister -- a role that was almost written to fail with its big emotional swings.
The shining jewel of the whole experience for me, the reason to have done Obi-Wan Kenobi the series? Princess Leia, as played by Vivien Lyra Blair. I saw a bit of whining about the character online, essentially stemming from overlooking the fact that Leia is ten years old here. In my eyes, the portrayal was an absolute triumph in both writing and acting. Basically every single moment felt like the Leia I've seen before, and often Carrie Fisher in particular. This little girl absolutely becomes the Leia of Star Wars.
I didn't need Obi-Wan Kenobi to be completely great, so maybe that's part of why I'm ok that it wasn't. (Hopefully, it's also because I'm not a toxic fan.) I give the series overall a B. Stronger by far than The Book of Boba Fett, probably not as strong as The Mandalorian when it's really firing, but worth the time.