First, doing it undermines the "regular guy sports cred" that the President has tried to cultivate through his attention to matters like filling out his basketball bracket on TV. His supposed obsession with sports has been the linchpin of his efforts to prove that he's just a regular guy, despite his penchant for expensive vacations and arugula.
Second, he is going to lose viewers that he was presumably hoping to attract in making the speech a television spectacle.
And finally, given the high profile he's giving this talk (and the fact that some may forgo football for it), he'd better have something that will knock everyone's socks off.
Think he can do it?