Luffy vs. Bellamy lasted like 2 pages and I personally found it more epic than Ichigo vs. Aizen. In my opinion the lenght of a fight does not make it necessarily good. On the contratory, dragging it might damage the awesomeness.
Definitely agree with you. That fight lasted, as you said, for a couple of pages, but was really epic.
Either way, Vinland Saga: Thorkkell vs. Thorfinn get's my vote.
Let me just say that Hunter x Hunter: Neteru vs. The King and Hajime no Ippo: Takamura vs. Hawk were also pretty good. And i don't need to say nothing about the DBZ's right ?