Board Thread:Theories and Speculation/@comment-35448581-20160502192848/@comment-734582-20160520170834

I think Kishimoto made the right choice. The Sharingan as an eye that reflects the mind, and grows with it is a great concept that he used pretty well, and he was right to focus on that more.

I agree that there are jutsu that don't necessarily make sense as dojutsu (the aforementioned six paths of pain), the Mangekyou powers seem to fit the eye theme much better. E.g. Amaterasu as a "look that kills". However i think that the lack of explanation on the Rinnegan is what causes the confusion.

In this context, there's a clear distinction between Byakugan (physical eye) versus Sharingan (Mind's eye). Sharingan matures via mental pain, but Byakugan should mature via prowess. After all, Byakugan's abilities are excellent base abilities to create truly ridiculous jutsu (as i have elaborated on before). Abilities like emitting chakra from all tenketsu is a significantly underrated ability.