He put a couple of good crosses in today, but neither Rashford or Martial ever attacked them. I don't see an out and out centre forward in either of those two. But that's a different discussion.
I think him being an overly defensive full back is a little overstated. He's decent going forward, not amazing, but he doesn't get a nosebleed when he crosses the halfway line like Darmian did. He's good in possession, keeps the ball and plays it when under pressure. I'd like to see him take on his man more, but apart from that he's doing fine IMO.