Yes now THIS I have pretty much NOTHING negative to say about it, EASILY the best episode so far and the only one (so far) I will rank the maximum 10/10.
Ichigo displaying a RAGE that even dwarfes what he displayed against Tsukishima, really gets across how much he cares about the Soul Society and the friends he's made there, and therefore how much what Mustache has done DISGUSTS him. This is Ichigo at his best, when he's just pissed off and fucking shit up.
Extending this fight was much needed as it makes Ichigo look a lot less like a bitch after being built up so much for the entire invasion. While I would have liked either Hollow Ichigo or a H2 transformation, I'm actually happy with what we got here.
The brutality of the original Gotei was about what Mustache described yeah, and having Mustache get back-stabbed by Chojiro actually explains a lot about how easily Yamamoto beat him before (and how little he knew of Yama's Bankai).
Yes obviously there is still the "twist" but my issue with it was never simply that it was there, it was how little it actually mattered going forward outside of serving to give Ichigo a generic power boost. So it will be up to later episodes to make a lot more use of Ichigo's Quincy heritage to make up for how poorly it was done in the manga.