Why wouldn't they do it now though? I'd watch the game at least for a few years if the pros were shitstomping the college teams the first few years and then after that I'd at least try to keep score updates to see if it was worth watching after the half.
Worst case scenario the college teams come in with a game plan to play absolutely balls out, fake punts/field goals, going for it on 4th down all over the field, lots of deep passes, trick and gimmick plays... Blitzes all to hell from every angle. I'd have the defense doing everything possible to create turnovers. Tackle hell... just do anything and everything to knock the ball loose on every play.
That would be much more fun to watch than the pro bowl.