I think he could have done well at 175, its easy to see that after Tarver, and he definitely could have handled 168, but I don't think he really needed to move up.

He always stayed in shape, and never seemed to have that much of a problem with making weight

If he does retire for good and he only fights once at 175 its a bit hard to answer. Was he that much better at 175 or was Tarver a really good style matchup for him?