Hansbrough is 6'9.5'' I don't see how he's undersized as he's bigger than Diaw. He wasn't too small when he was ripping the wolfpack to pieces ;)
Kevin Love has nearly identical length, more weight(strength?), and better shooting range. But he doesn't strike me as having Hansbrough's level of quickness. From what little I've seen, Tyler can D up perimeter bigs pretty decently.