Board Thread:General Discussion/@comment-24815992-20140426145103/@comment-24867665-20140427002456

They were at full-strength, but I do think most captains didn't use Bankai so they could fall back on it as a last resort as it might take a lot of strength to do so... such was the case with Isshin's if you recall that he couldn't release his Bankai from being too injured.

Some captains' Bankai states could also be too overwhelming, like Yamamoto's. Don't want to be releasing something that might end up destroying the pillars as well.

=)