Being a Heisman winner doesn't mean anything. Half of them end up failing miserably, and the ones that don't generally aren't any better than average.
College football is different than the NFL. Teams are different, players are different, schemes are different.
Henry doesn't really impress me that much. He's still one of the highest RBs on my board, but he lacks the tools to be an every down back. Since we are talking about Heisman winners, he actually reminds me a lot of Ron Dayne.
If the titans use him correctly like I think they will, he will be a decent success. Not worth a second round pick, or giving up Alexander and Bell success, but at least not a what-were-you-thinking failure either.
I still think they could've gotten away with Antonio Andrews as their change of pace for Murray too.