David Moyes came out this week to say that he believes Fellaini's failure at United last season, and his own, was because of a lack of signings.
Perhaps Moyes' failure can partly be attributed to this, even though many will argue he inherited a squad that won the league title the season before, and his failure was simply due to him being overawed by the circumstances and lacking the tactical acumen to dominate games, as would be expected at a big club.
Instead he tried to get the team to play like his Everton sides, which isn't good enough at a big team like Manchester United and it really showed.
But to blame Fellaini's failing last season last season on this is simply wrong. Instead, it was David Moyes misusing Fellaini, pandering to Fellaini's belief that he's a "playmaker". While Fellaini has many qualities, I doubt many would count playmaking and picking a pass as one of them.
Moyes played him in a central midfield duo last season, and Fellaini simply lacks the skill to play this role, his lack of ability on the ball means he is a liability in possession when picking it up deep, and he is unable to pick a forward pass or retain possession in a congested midfield.
Van Gaal has realised this this season, and has played to his strengths by utilising him as more of a deeply lying target man, pushing ahead of the midfield to provide United with an outball when necessary and support Rooney in the box whenever possible by peeling off to the back post and providing a potent area threat in the box. This utilises his amazing ability to bring a ball under control on his chest, as well as his sheer physical presence which can make him almost unplayable at times.
His use as a "deep lying target man" has been nothing short of genius by Van Gaal, though Moyes did use him in a very advanced position for Everton often too to be fair. What is shocking is that, after so many years together at Everton, Moyes did not continue his tried and tested formula with Fellaini, and instead tried to use him as something he simply is not.
This is evidenced by the success Fellaini has had in the last month and a half. He has been playing alongside players all of whom were at the club last season (Young, Carrick, Rooney, Mata) with the addition of Ander Herrera and Blind, and yet still put in far superior performances to those of last season.
I think the minor differences in personnel have nothing to do with Fellaini's failings last season. Instead it was him being utilised completely wrong by a manager who clearly can organise a side wonderfully well, as his success at Everton and now Sociedad shows, but lacks the tactical ability to create a dominating, world beating team.
This is obvious when comparing how van Gaal, a proven world class manager, and Moyes have used Fellaini. It's yet more evidence that Moyes was out of his depth at United, which probably doesn't need to be further emphasized.