Board Thread:General Discussion/@comment-9732657-20130519011726/@comment-9732657-20130520184214

That contradicts the very definition of an arrancar, a being that tears off its mask and seals the nuclei of its powers into the form of a sword. In the first place the Visored are masked warriors, the name itself stems from the visor on a knight's helm.

Arrancar have a Hollow base and are imitations of shinigami, while Visored have a shinigami base and go insane due to the melding and chaotic, cognitive dissonance of two souls. By definition White was a Visored who had reached its final state of development, thus transcending shinigami and hollows. His base was too weak to form a truly peerless adversary akin to Aizen and Ichigo and his lack of coherrent thought made him a lethal fighter, but a poor survivor. Further more, Arrancar don't experience Soul Suicide.