Hey, that's my line.
I speculated about that myself here a few months ago, before it became clear how dismally inept Romney really was.
So I don't entirely disagree with you on this, but on the practical side, its neither early enough in the campaign to do that smoothly, nor is it really necessary. Barring an unforeseen October Surprise, Obama will win.
Besides, Joe has shown himself to be a very effective close-combat street fighter, in spite of his carefully cultivated reputation as a bumbling oaf. Paul Ryan is going to learn that the hard way in the debates.