Of course he has, he's miles better than what we had before in that position. He's done his job, much better than what was there previously. Isn't that the whole point of transfers, buying players that greatly improve your team? His defensive positioning is light years better than McTominay and Fred.
I feel people really take him for granted, and forget just how terrible McTominay-Fred midfield was. We went from mid-table midfielders to Champions League level midfielder. Even last week only he scored the winning goal and carried the midfield!
We would not be in the top 4 without Casemiro this season. Also you're adding £10 million onto his price seemingly to make a point.