Here's what I don't understand about the 2 DM setup. Every week, Gana finds himself in areas in or around the final third where he needs to find a good forward pass and he doesn't have the skills to do that. The space is there but we're wasting those opportunities by giving them to a player who isn't good at moving the ball, especially in tight areas.
Why not drop one of Schneiderlin/Gana, ask the remaining DM to stay deep, and take a defensive downgrade at the open position to add quality in the final third? If we were to do a better job of keeping the ball in attacking areas, the defensive downgrade might not even matter.