The Final villain should be a hollow(like a zomg king of hollows that isn't loyal to Azien), Sado hollow(at some point he dies & becomes a hollow. His abilities are hollow based & he's extremely powerful for still being in a mortal body. Note: Ichigo is tecnically dead based on how he regained his shinigami powers) Ichigo's hollow(some twisted plot device to separate the hollow from ichigo's body) or the SS King(make squad zero enemies of ichigo. It could happen with the right setup). Fuck Azien he's overrated at this point. I really hope the Viz end up turning on the shinigami after Azien is taken out. I don't see Azien as the final villain case in point he's the first zomg big bad in the series. The first should never be the final expect Azien to be taken down with the manga continuing without him.
Edit: Ichigo also needs to talk with Zangetsu again. He's relying way to much on his hollow abilities when he hasn't even mastered hsi shinigami abilities.
Note: deleted my older post & moved it here since I have too many post in a row because of pictures.
Edit
from 2ch