Not sure ANY manager could have done any better with this set of players. Too many (for Man U) over the hill players, too many of whom have been more concerned with their want away plans for a final pay day, amongst whom is the team's actual and natural leadership, setting a poor, and confusing example to the young players .. Particularly I suspect off the match day pitch.
Key players Shrek and Van Pursestrings are amongst the most temperamental, and indeed belligerent players in the PL, strongly motivated by money and self interest, almost choosing when they will play and whether to put in a full shift when they do. bad enough having one player like that in your team, but two of them and they make up your strike force!!
Finally some of Fergies recent buys have been found out, not that they are bad players but they are just not good enough to help Man U win and indeed stay at the elite level of football. I am sure Fergie would have already been planning the replacement of some..