It's more complicated than just a holding mid. When you look at Rashford, Sancho and Greenwood, they wouldn't look out of place playing for us wide in a 4-3-3 but then they've got Fernandes that wants/needs to play in a 4-2-3-1. You can't really fit Pogba into a 4-2-3-1 and then there's the Ronaldo issue. You only have to listen to Neville talking about needing to play Cavani alongside Ronaldo - where the hell are Utd playing Fernandes/Pogba and all those wide forwards with a front 2?
The squad is unbalanced.
Ok, to an extent I agree. But taking things back to Ole, the lack of balance in the squad is at least partially his doing. He's had no plan, so has effectively bought good players at random as they become available.
And I would still argue strongly that a good manager would do much, much better even with this squad