Board Thread:General Discussion/@comment-10786787-20130613005503/@comment-5693502-20140608200725

Melee-type zanpakutō don't usually have special abilities associated with them. Also I'm quite sure every known melee-type zanpakutō changes its form upon activating full release of shikai (the only exception really being Sanpo Kenjū - though even that's debatable).

The full release of Kenpachi's shikai just seems like it gives him a bigger blade meaning it has a larger range, more force can be applied with each cut, more damage can be inflicted etc.