Along with Moyes, Van Gaal will be remembered as Utd's worst ever manager. Both of them were to Utd what Souness was to Liverpool. He was that bad. Spent a fortune on mediocrity while he sold superior players like Chicharito, Evans, Welbeck, Kagawa for peanuts. Played the worst style of football not only ever seen at Utd but in the history of all leagues in the UK. Like Moyes his methods were the opposite of what Utd is about and he was 20 years out of date with his methods. Moyes was different in that his methods suited clubs like West Brom, or the Wimbeldon team of the 90's who only had one tactic to pump the ball into the box into some giant brain-dead monster to get on the end of it.
Van Gaal should have been sacked long before he was but I honestly think Ed was seriously thinking to give him a final 3rd season if he made the top 4 and that was only confirmed on the last day of the season so that's why the board rightly waited. Thank God he never got that 3rd season as there'd have been no Europa League win, No Pogba, Bailly, Mkhitaryan, Lukaku, Matic - Christ he would have done unfixable damage had he stayed a 3rd season.