It was, you're right, but this isn't really Rooney's game. Rooney thrives from pace and width around him. Playing a 352, with Borthwick-Jackson and Lingard, especially as they didn't really get forward that much, meant that Rooney and Martial, when they got the ball in wide areas, were crowded out. For example, Martial's run when he had three So'ton players around him. It was literally just him.
I think it was no surprise that we saw a bit of form from Rooney with Lingard and Martial on the wings. Neither have been pulling up any trees of late, but the pace and running behind allowed Rooney to play his natural game. Again, Lingard's goal vs Newcastle is an example of that.
Think Van Gaal needs to go back to a 4231, with Martial/Depay on the left and Januzaj/Lingard on the right for the next game.