Lukaku is also the only left footed attacker we have, and Jose likes to play with inverted wingers/forwards. From the times I have seen Lukaku out on the right, he does more than a decent job.
I think his dribbling when given space to run at a defender 1v1 is not too bad. It's when the space is tighter and he had to deal with more than 1 defender when his lack of close control betrays him. Aerially he will give any LB a huge problem to deal with as well.
The thing with Lukaku is - all we have him currently be is a target man who plays centrally which handicaps his own current game as well as the game of others around him.
Forget Sanchez for one sec & picture this -
Rashford(RS) - Lukaku (LS)
Martial (SS)
Lukaku's strength is more running behind the defence that necessarily try to take his man on ( that again is the role of a winger & not a sided striker). However just because Lukaku struggles as a target man centrally having all the balls coming to him - doesn't mean he will struggle as a Right sided forward that the left sided forwards like Rashford & Martial play off of him. That stuff could be deadly.
A left footed on the run sort of target man on the right and having Rashford & Martial playing off him just off to the left of him.
Can you imagine martial starting the attacks from deep, laying the ball to Lukaku to the right & then martial overlapping Rashford to receive the ball on the left. if they don't score then Lukaku will automatically be at the back post anyway due to his placement.
Rashford could be deadly predatory in that situation.
Sanchez could replace anyone in that front line & do just as well or better. Lingard himself could be the more defensive version of martial the ss whilst fellaini can come and replace him as a emergency target man.