It'd explain a lot. For one, it would explain why Hidan and Kakuzu are in Konoha; the only other explanation would be that they were there for Naruto, and that, for whatever reason, Itachi and Kisame were taken off the case. For a second, it'd explain why he was suddenly brought out of nowhere to be part of a main arc. For a third, it'd explain why he might be the 'strongest in his generation.' Sai certainly seems to fill the jinchuuriki qualities as well, ie being (mostly) alone and by himself, for the most part. What do you all think?