I'd love him at United. We'd have to sell Pogba first, but I think a shift to 4231 could be of benefit overall.
In the last three seasons:
Pogba has 6, 6, 5 non-penalty goals
Coutiho has 5, 15, 13 non-penalty goals
Pogba has 9, 10, 4 assists
Coutinho has 2, 11, 7 assists
Obviously, Coutinho is coming off a relatively poor season for Barca, but that's because he's competing with Messi for space in the hole. He won't have that problem at United (assuming Pogba goes to fund the deal).
Ole is trying to solve an almost impossible puzzle to create a system that can accomodate a luxury player in a team that isn't good enough to carry him when the going gets tough. The easiest solution is to throw the old blueprint away and opt for an XI full of specialists in every position. Those who like to defend can defend, those who like to attack can attack.
A proper #10 in front of a double pivot would be a quick fix to a years old problem. And the defensive midfielders we need might possibly already be at the club.