I like the Pervy Sage myself. He is one of the Legendary Sanin and he also trained one of the strongest ninja who've ever lived, being that of the Fourth Hokage! Jiraiya is in my top five favorite shinobi.
I believe pervy sage is a key character in the growth of Naruto, he trained Naruto's father the Fourth, so who else would be a better sensie, than the man who trained his father. No one else could fit in that role, not Kikashi, not Tsunade, not nobody!:2thumbs:Scorch