Personally, I think some people at United don't want Jose simply because of the trouble he causes and they want to maintain their reputation and don't want to be embarrassed on a regular basis. I don't think they want the baggage he brings, as I think they still see themselves as being better than that. Fergie caused trouble on numerous occasions, and the club always backed him, but I don't think he would have been taken on in the first place if he had acted the way he did at United at other clubs prior to his arrival (falling out with the BBC is a perfect example). I can understand their point to a certain extent, and agree that reputation comes before success, again to a certain extent, but I think that it has gone past that with the appointments and failures of Moyes and LvG, and that if there really is nobody better, then they should and have to go for Jose.
Fergie and Gill and Sir Bobby made it abundantly clear that they wouldn't tolerate any player being bigger than the club and that point was proved time and time again with players like Beckham, RvN and Keane being given the boot, and I think they obviously feel exactly the same way regarding the manager of Manchester United. And although I agree with that sentiment completely, I honestly don't think Jose would think he was bigger than United, and hopefully the way he left Real Madrid and more recently Chelsea would have taught him a little humility and maybe, just maybe, Jose and United would compliment each other perfectly.