The second arc in the manga, and one where the cracks that were already visible in the first one are beginning to fully show themselves. An abundance of filler characters, or characters with little distinction that are trying to create artificial drama which doesn't really exist, the full definition of fodder. Even beyond that, more and more new characters are introduced, with little time to get to know them, to learn about them, to be fascinated, scared or excited about them.
The plot itself is becoming more and more contrived, with a lot of plot-points feeling like retcons, backwards justifications, or deception. The inherent problem with lies is that if you overdo it, readers will become less and less invested. If someone is capable of undoing sensible cannon, to the point it stops making sense, immersion is utterly and completely broken. I didn't get quite there, but I was close. The big reveal of how Aizen had engineered Ichigo's entire journey and growth also feels rather cheap, though I suppose this 'covers' a lot of other plot holes.