Interesting stuff: If Ronaldo + James go, you need to bring on quality to your attack of course.
But really what RM should think about is if Casemiro is good enough for his (crucial) role, or if somebody should be bought there.
I don't know if RM would play Pogba there - he is too attacking-minded for a DM-role, isn't he?
I think Pogba does well when the whole system does well, I think he is terrific in a 4 4 2 where the midfield moves together in a line. He is not a holding midfielder, and so far Casemiro has done a fine job but I don't think he is great with Kroos because neither of them are fantastic dribblers or carriers of the ball. Kroos can distribute and Casemiro can destroy, so the load is on Modric to carry and dribble the ball. The 4 4 2 is the system we have in defense and 4 3 3 in offense, this suits Pogba.
While I think Pogba does well with both Kroos and Casemiro, I don't mind him replacing Kroos to be honest. However, if Ronaldo is not gone, then James is definitely gone, because this 4 4 2 / 4 3 3 hybrid is definitely requires an intelligent winger with high work ethic. When Bale on the right started putting in work, the system made sense. Under Rafa, he didn't help out and we suffered major loses. James however is not a winger, he cannot run the distances for a long period of time. He is being utilized in the league and so far its working but I doubt it will work against Barcelona or Atletico.
I still maintain that James should stay, along with Isco and that Ronaldo is the one that has to go for the future. I still believe that James-Benzema in attack and Isco-Casemiro-Kovacic-Bale in midfield is the future. Marcelo and Carvajal more than provide width and attacking excellence. Isco played under Ancelotti really well on the left wing as a decoy, and he has shown he can put in a defensive shift if necessary. Kovacic is basically Modric with a little more defensive grit but he is the future no doubt. He has the ball carrying skills and Casemiro is the 3rd center back that covers for Ramos' bursts of action.