We have never got a really good look at him in a 4-3-3 anyways.
Playing RM in a 4-4-2 is way different. More defensive responsibilities. More energy lost. You play deeper and don't get many chances to get in behind. Not many chances to be 1 on 1 with the fullback, etc.
To be honest, I never thought he could do this well in a 4-4-2. Thought he would be way, way lazier. Way more wasteful in build-up.
I would love to see him in a 4-3-3.