If Sanchez is that mentally weak, the Jets will be better served finding that out now. How many "elite", playoff-quality QB, would be concerned with Tebow standing on the sidelines? Shouldn't teams strive to have playoff-quality QB?
AC, I've already said Rex could turn it into a circus. Or he can make it work. Fans don't call plays or set line-ups. As long as Rex doesn't bench Sanchez during a bad game or start "It's an open competition"/"we evaluate each position every week" discussions, there won't be a problem. Tebow isn't going to yap to the media about more playing time. The Sanchez/Ryan relationship is the potential problem not Tebow's presence.