They split Gill & Ferguson up as they'd pulled a few fast ones to get what they wanted but they should've kept together for a while longer and planned thr managerial succession better.
This, more than anything else, explains their downfall.
Fergie was getting on and they should've handled him leaving far better. In fact, it's hard to think of a worse way to do it. The new man should've come in and worked with him and got to know the culture of the club. This was a fairly unique club in that he ran the place, top to toe whereas everyone now had Directors of Football etc in place.
Moyes came in and got rid of many of their staff and brought in his own men. I can understand why he would want his own men in, but he should've kept them on for their experience. It really showed his naievity, he wasn't a Mourinho/Guardiola/Ancelotti who had a track record of success. At this point now, the 'Fergie United' had gone and by the time van Gaal had got rid of Vidic, Ferdinand, Evra, Welbeck, Evans, Hernandez etc it makes you wonder if there was any part of it left. Other than the pisscan turning up to see them get beat and booed at home, his dynasty had completely gone.
Mourinho's character and style was well known and he did well there. His style of football was at odds with van Gaal, Moyes and Fergies. He came and went then Ole comes in who's counter attacking, looser style of play was again at odds with Mourinho's style. Ten Haag wants to play like us, but he's got a squad of players who aren't suited to his style.
Contrast that with us and Pep. When he came in, half the squad could adapt to his style and the players who couldn't went fast and were replaced by ones who played his style. The club now is the best run club in world football. When Pep goes, the next manager who comes in won't be Simeone etc it will be someone who plays the way that Pep, Soriano and Bergistrain play. I really don't understand why they aren't trying to copy what we do!