renji can still move fast with his bankai
byakuya got grace and lots of power in his bankai
hitsugaya have many variations of his bankai, just like byakuya
komamura bankai is dead slow and has too many weakness, its only good for intimidation only. pass the intimidation, its juts another big dummy
ikkaku is still very reluctant to use his bankai, as we all know, he does not want to be pressured to fight kenpachi for the captain's post
but even with his bankai, i think he can only land a few flesh wound on kenpachi before he finishes him off with one or two slash, the most
Added on February 10, 2010, 8:11 amshinigami have rules and regulations for them to abide with, if not, the whole sould society will be chaotic. unless soul society have this gladiator arena whereby anyone who believes himself/herself to be strong compete, they have to follow the necessary steps to ascend to greater powers. like knowing your sword name, then training or fighting as a team and then do that for a few decades or hundreds of years to attain bankai and then controlling it
as for the arrancar, its more like the strongest, fastest and toughest survives
the only thing that puts the espada and privaron in order is their absolute fear (and some respect) for aizen
*one of the best moment is whereby aizen brings grimmjow to his knees simply by releasing a little of his aura...

reniji can move faz after bankai, but his baboon king moves slow. And it's more defence oriented.