I'm actually hoping Moyes goes soon now, so we can find this world class manager to turn it all around and we can stop hearing about back room staff being changed like it's this new concept when a manager comes in.
I highly doubt even Mourinho could get anything out of that shower of a back four.
In the very vast majority of cases managers leave a club because they have been failing, not succeeding. Very rarely does someone retire from a top club, when a team of manager/coaches are failing, replacing them all makes sense to some degree, but a large part of that is because the coaches brought in have worked well with the manager for years.
Moyes went to a job at a club vastly bigger than anything he's previously experienced, some of his coaches, Neville for instance, is very inexperienced at any level, in that particular set of circumstances when there is an existing experienced and highly successful backroom staff that, importantly, have been getting the best out of the existing squad for years...... it was utterly brain dead to get rid of them.
Comparing it to say Palace firing Holloway, where he sucked badly, his coaching wasn't working, and a new guy coming in and installing his own staff(I'm not sure Pulis did at Palace) would make a lot more sense.
I said for quite a long time that Wenger's coaching methods, his "ultra fitness" campaign he waged for years was hurting us badly injury wise. Then he started treating RVP like an individual, and he went 18 months uninjured, Fergie treated RVP like an individual, went uninjured for a full season in which he won titles and was key to that, Moyes treats them all like robots who are identically physically capable, RVP is constantly injured.
Wenger still has his "player fit, never heard of rotation, he'll play till he's injured" mentality, which has still cost multiple injuries since, and Moyes has done this also, though publicly admitted this was mostly down to fear of fans reaction.
Had he kept on some of the backroom staff they may have explained to him that RVP training differently kept him the best striker in the league for three years.
Moyes is a manager who had limited budget, limited staff, limited expectations and appears to be trying to translate the Everton way of doing things on Utd, rather than trying to change himself to learn how to run a much bigger club.
Wigan couldn't afford a physio and coach to individually train top players most likely, Everton probably couldn't, Utd can. Just everything he's done, his mentality, he still hasn't done anything at all to suggest he is remotely ready to adapt to the requirements of managing a team of Utd's size.
People have been banging on about top players, it's rare for truly top players to leave top clubs. While Ronaldo was great at Utd, he's still moved on to a completely different level at Real, if he was a 60-70goal a season player for 4 years in a row while at Utd, Real couldn't have afforded him. £30mil or £60mil Cesc didn't want to leave, this was clear as day.
They should have been identifying realistic targets over summer, younger players, guys who like Bale(but without the overhype-ness) had improved for 2-3 seasons in a row and were likely about to get really good, the guys who play anywhere below top 4 clubs that you can actually get. Going after a first team starter at Barca, who had been consistently their second best player for 2 years, who loves Barca, who loves Arsenal as well..... outside of Ronaldo and Messi I can't actually think of a less available target to Utd.