[quote name='Pyro Fighter']Can't remember the specific chapter, anyway, I think that I got what you mean though loosing an arm is something big indeed.
Well, have you noticed that Jozu never even once covered his body completely with diamond?
Is he doing that on purpose or rather, he can't?
And why didn't he stay in that mode until the battle finishes, I mean come one, that was the reason why Aokiji got a chance to break his arms with ice, yes?[/QUOTE]
I totally agree, but if he stayed in diamond mode, he would be nearly impossible to beat (without haki)
Therefore restrictions apply a lot in One Piece from Oda's persepctive. If they didn't, Kizaru would be the strongest guy in One Piece, WB would have merked all in the Marineford War by destroying the whole town, and Kuma would be near-invincible too