I don't have an issue with him playing deeper, but I think if he is to play deeper he needs the right kind of players in midfield with him.
Ross's strength is as a pivot, firing passes to a player and receiving it back to move further up the pitch. If his intention is to sit, he needs to be surrounded by players that will make runs off him to move the play forward, bringing the striker and wingers into play.
McCarthy isn't that player, we very rarely see him make passes that aren't sideways or backwards, and he doesn't burst forward.
If Ross is going to play deeper, would like to see him with Besic, who is more likely to pass and move forward with the ball at feet, and who also has a better passing range. Ross suits a high tempo game where he can buzz around people with quick passing. That's his strength