Let me preface this by saying that I've read the entire manga during release, and own the volumes. I'm a huge BLEACH fan that has played pretty much every game, read all LNs, watched interviews and closely followed Kubo-sensei. In my opinion, this season's finale undermines severely the structure and message of the series, in particular the final arc.

I don't even know where to start listing what I dislike about it, so here are some scattered thoughts:

1. The 0th squad was supposed to be defeated quickly, narratively. It established the Schutzstaffel as formidable foes while simultaneously saving face (they were defeated by surprise) and avoids potential nonsense with their Bankais. Now we get some absurd stuff about "their powers being too great to release", yet Ichibe is fighting with Bankai just fine, and later on Ichigo's bankai doesn't destroy all of existence, despite being by far the strongest thing to ever exist, after the original Soul King.
2. To add all of this filler in their tight 52 episode schedule, they had to cut out a bunch of great moments of silence where the audience gets to really think things through and understand the characters and their motivations. As a result, pacing gets demolished. If the filler was simply expanding on what was already there in the manga I wouldn't mind as much, but they're adding stuff that makes no sense in-universe.
3. WHY CUT OUT THE BIG REVEAL FROM THE SEASON FINALE? Worse still, what was originally a "oh shit, this might actually be unwinnable" moment in the manga was relegated to flashback in this arc.

Anyway, there are a bunch of other negative things I have to say about this adaptation, but overall I'm still enjoying it, bar some moments of real annoyance. I just wish they were more faithful to Kubo-sensei's original work.