I think Kelly will have to run eventually, or he won't be the first WR taken. Honestly, I'm not sure he's better than Jackson. Say what you want about Jackson's size, he can flat out stretch a defense.
I don't know why Reggie not showing up to the pro day is a big deal to most people. If he's not healthy enough to workout, what could he possibly have to gain by going there? I'm sure he's at some training academy in Florida or Arizona, so I don't know why he'd want to come back to OU just to interview with teams. Not being there doesn't reflect negatively on him at all, especially if he already has a workout already set-up in the future.