Notice how this has happened for several player under LVG. After a good start, players become proper LVG players and start to slowly have shitty performances one after the other.
Almost exclusively true. Di Maria - started off very well, then faded and became completely shite towards the end of season. Falcao was decent in the first few outings and then terrible (admittedly he's still terrible after a year). Darmian started off very well and is now a shadow of the player he was, Herrera was good at the beginning but the more he plays, the worse he is. He was the best when he came back after a long time out of the team, which earned him a spot on the bench again because he was clearly not following philosophy. Depay has promising first few games but then got completely crap, Martial was incredible in the first 4-5 games but he hasn't been anywhere near that standard since and has looked almost scared at times.
Shaw is the only player who started to grow into his role under van Gaal. The rest of our new signings have either played reasonably well filling their rather limited role (Schweinsteiger, Schneiderlin have been system players mostly) or regressed.