I think that even though Diogo Simone has achieved lot with this club winning the laliga title and playing in the finals of the champions League some years ago he has ran out of ideas and has over stayed his welcome the best thing is for him to move to another club because at it's stand now ATM is now a club that has no ambition both in Europe and in the domestic league
The game keeps evolving year after year and as a manager if you are unable to evolve with the game you will be left behind. This probably is the case for Diego Simone at Atletico Madrid, I also suggest a new chapter elsewhere for Simone hopefully this could help him get fresh ideas and a fresh start.