It's not because he doesn't fit a system that a player is "not good enough". Mata apparently was not good enough for a team that wanted to win the European Cup, yet he ... WON THE EUROPEAN CUP. That's kinda stupid, isn't it. Mata is just not a player that thrives in Mourinho's system. Doesn't make him bad. Same with KDB, who is younger than Mata and is improving every year. If he continues dominating like this, he'll get another chance at the very top. I guess for him that means staying in Germany though.