Board Thread:Theories and Speculation/@comment-35448581-20160502192848/@comment-35448581-20160519175438

The thing is that at the beginning of the series a Dojutsu was just something the eye itself did, i.e. the Byakugan’s near 360º field of vision, enhanced range, Xray, the ability to see chakra in great detail, etc. Or the sharingan’s ability to see chakra (with less precision than Byakugan), great clarity of perception, the ability to see fast-moving objects and anticipate an opponent's next move and the ability of memorize and copy almost any jutsu they see with near-perfect accuracy. This changed letter on with the introduction of the MS, which can actually cast jutsus.

About Rinnegan, or more precisely, the abilities of the six paths of pain, it has always seemed flawed to me. As you say many of them are performed trough the hands or by physical contact. Which leaves one questioning about the actual powers of the Rinnegan. According to what a dojutsu originally was meant to be, its only true Dojutsu powers are its ability to see chakra and to easily understand any jutsu (similar to sharingan). The six paths of pain seem to have been mostly devised by Nagato. The shura path specially looks too mechanical, it doesn’t look as something originated in the eye nor even in the user itself (shouldn’t that path dude still be made of flesh and bones if so?). To me the shura path should have look more like the jugo’s clan transformation, linking them to the Ōtsutsuki and somehow explaining their power.

Anyhow, let wait and see if the current filler helps answering some questions.