I've got no problem with this move at all. Most of the examples used for not coming back are only examples because the prospect was overhyped as a junior. Sure Bradford got hurt, but came back bigger and stronger and went #1 and hasn't missed a snap. I don't see how he is a case study for coming out early. Sure Leinart dropped to 10 but that is because he wasn't that good. It is the same reason why he is #3 at Houston. Coming out as a Junior wouldn't have helped that, it would have just made him JaMarcus Russell or Alex Smith, and is that really what you wanted to be.
I would honestly rather be John Beck than Alex Smith. Beck has still made more in the last few years than I will in my career, but gets spared most of the ridicule. Locker could have come out last year and been #1, gotten a huge pay check and been a national poster child for unacheived potential. His draft stock suffered because this year showed people that he isn't all that good.
Luck looks like the real deal, and if he is then he won't be missing much by staying in school and finishing his degree. The team may not win as many games as they did this year, but as long as he plays well and ends up in the NFL then he will be fine...Fine? He will be a multimillionaire next year.