Well that's great. Van Gaal disagrees. Welbeck, Mata, Kagawa and Rooney will continue to play matches out wide. I'd rather Mata in particular played at #10, but the rest could play there fairly easily.
Wide forwards are not wingers, they position themselves to score. Januzaj coming in off the right, and yes, he's good enough to be relied upon - age is simply a late Ferguson excuse to stall - and Welbeck, Rooney or Kagawa on the left could all perform well and score goals provided the football was progressive and compact.
A team with Mata at #10 is scoring goals, that's a certainty. Herrera has something about him, Van Persie central is an incredible target man. Rafael and Shaw will bomb down that touchline day and night. The signing of a Sanchez or Di Maria isn't the be and end all. Van Gaal will hopefully play to the strengths of the players we have, and central football through the likes of Herrera, Mata and Van Persie, with supporting runs from players like Welbeck, Rooney and Januzaj is certainly workable. Perfect? No, but we'll score goals next season. Kick back and enjoy them.