1. ETH decided to replace De Gea with one of the most expensive goalkeepers ever. So, for ETH, we have upgraded. ETH believes he is the second best keeper in the league. And anyway, it was his decision, that cost us 50 million or so, money that could have been used to strengthen other positions.
2. ETH had a quarrel with Varane. This kept him out of the first team for a while. And may have contributed to his poor showings. -Varane is a model professional, this was poor man management from ETH.
3. We are not sure what happened with Casemiro. Some say that again there was a fight with ETH. And anyway, ETH got Amrabat as a replacement, a player he requested because he knew him from Ajax.
So, these three were basically the manager's doing. Only Martinez was not his decision.