What always (well not in every fight, but it happened often) was strange about Bleach and still is at this point in this episode - the autor has not implied an essential need for Ichigo to use the Final Getsuga Tenshou. He was way stronger than Aizen before his "last" form (in fact Aizen looked like an ant) and although one might want to argue that he got way stronger afterwards, Kubo did not visualize that Ichigo had to sacrifice his Shinigami powers by using the Final Getsuga. Aizen got him with that weird reiatsu circle prison whatever, but Ichigo didn't even try to get out of it without using his final resort. Aizen just "evolved", grabbed Ichigo and that was enough reason for him to risk sacrificing his powers without knowing that Aizen would regenerate? Actually he saw him regenerating before, so it WAS an incredibly stupid decision to risk using it (or isn't it even worse? I mean didn't he kinda kill Zangetsu by using it?), as he obviously didn't seem to know about Urahara placing that sealing kido on Aizen. If Kubo wrote it in a way, that would have let Ichigo known about Urahara's plan or Ichigo wouldn't have a choice but to use the Final Getsuga, cause Aizen was stronger than him without using it. But he did neither. So this just looked plain weird.
Other than that a solid episode. By far not as good as the last one and way too short for a final fight (about EVERY fight before this took WAY longer than this one). I'm not essentially complaining it wasn't ten episodes long, but one and a half episode really is too short for a shounen counting 300+ episodes. Kinda feels like they got it the wrong way around. It wasn't incredible, but ok (although imo not final fight worthy) compared to all of the serious garbage in the uberly dragged out war shit arc. Still, I don't want to praise Kubo for partially completely fucking up the "ending".
EDIT: Oh and, about the too obvious and stupidly enacted reasonings between Zangetsu and Ichigo - I told you, didn't I!