I believe that Amorim is a coach with high taste of quality players and it does not mean that the player must be a superstar. The management is desperate to see a new Manchester United full of strength and zealous to win trophies. United performance has been poor for so long and it doesn't tell good about them because they have lost their respect.
Indeed the Portuguese is a great coach who has shown great prospects when he was in Sporting Lisbon but coming to Manchester United, alot changed for him because he met a weak team and you don't expect him to perform magic because you need money to put a great team together and I don't think Manchester United has such financial strength to facilitate such project. For me, I wouldn't say the coach has done badly so far, but I think if the club can come up with the required finances then the coach could do better come next season.