The thing that irks me the most about Sancho isn't necessarily Sancho, rather than United's transfer and development strategy. What was the plan with Sancho? Play him on the right? Then why break the bank for Antony, and getting promising youngster in Amad who also was expensive signing for his age?
On the left? Then what with Rashford? Surely by then they realized he's not a out and out striker, so was the strategy to sell Rashford? Fans would be fuming if that would happen, he's as Red as they get. Then you search the academy and you have Elanga, who's progress has stalled for many reasons, one of them being not playing consistently enough. Also, looking down you'll see Garnacho, who's been tearing it for 3 seasons now.
As attacking midfielder? No one in the world is going there ahead of Bruno. Maybe drop Bruno in Eriksen position, but Bruno is not known for having the discipline or positional sense when it comes to defending.
Now you're left with a player who you can't play because you spent 100m on Antony, Rashford is undroppable for anyone and Sancho isn't a striker. Not to mention that young players who are playing in that position are playing great and they need playing time. You actively did not leave a path for Garnacho and now that Garnacho has emerged as a Rashford deputy, United have a problem.
Where does Sancho play?