I think there is an argument for selling the likes of Keane and Lingard with buy back clauses. Loans do not always incentivise the loaning club to play the lad, whereas if they have bought them there is a definite likelyhood that he'll be in the starting line-up. Lower premiership teams are more likely to take a risk on a player that they invested a couple of million on than if they've stumped up for his wages for a couple of months. If the move pays off we buy him back at a much lower fee than if he was your normal English lad moving to United. Win-win all round.