Well, Kubo was in a kind of rut and the show lost traction.
I have to say I hate everything about Ywach and that arc. The only thing is that it explains what happened with Ichigo's mother and kinda explains why Ichigo is compatible with so many powers.

Other than the arc itself, I have a blast with the cinematic animation, not perfect 100% of the time, but far better than what we have nowadays.
For some reason I get nothing from the OST when it was what got me hooked to Bleach in the first place. It also shaped a huge part of my J-music tastes with all the major hits it produced.