If we get Sanchez and Luke Shaw holds down the left back spot, we'll be in a comfortable position in the summer. Most of our starting spots would be sorted out with just a few holes to be filled.
De Gea
Valencia Bailly Jones Shaw
Matic Pogba
Sanchez Lingard Martial
Lukaku
The players in bold do not need to be upgraded. Lingard and Shaw have half a season to seal their spot. Valencia will be 33 when next season starts. So we might need an able deputy to take over.
We might sign a No.10 like Ozil or another midfielder instead of Lingard if he doesn't maintain his current form. Shaw and Young can share the LB role if all goes well. Else Rose or Ghoulam might be a good option. We'll need a new RB since Darmian won't cut it.
Players that could possibly leave this summer are Darmian, Mkhi, Blind and Fellaini. I wouldn't be surprised if we decide to sell Mata and Herrera as well.