No doubt that Rashford was fantastic some seasons ago but he has not been consistent in recent seasons that was why he has been left out of the squad plus looking at the financial situation at Manchester United they can't continue to pay huge salaries like that of Radford as the club is looking at a new beginning with different players.
I believe that this Barcelona move is a good one for him because he will be a back up striker helping lewandoski he was good in his loan spell with Aston Villa so I believe that he can come back to top form and make Manchester United regret the decision that they take
Last season Rashford was having more of a problem that i wouldn’t say is football related but seriously the lad is not a push over player, he still has the potential he possess years ago. I believe if he can actually get his past antics behind him he will most certainly be back in top form again. His problem with Manchester United had much of nothing to do with his performance but rather was about his outside football life which he has to changed and if he keeps up with that then he will be most certainly not stay for long in Barcelona too.
Concerning his position people think that Hansi Flick prefers Raphinha at the left wing position but No he simply had to last season due to lack of quality players at that position, I think with Rashford been available he will most likely use Raphinha at the 10 role just behind Lewandowski