The only downside he has is he is the highest paid manager of all time. He should be paid well enough, but 15 million is more than enough, even maybe 20 million would be a lot but acceptable, this dude made 30+ million for a while and now back to 30 million. This is way too much, most players do not make this kind of money, only a few players make more than him. I understand he is a great coach, but even the greatest coach shouldn't be making this much. In theory, the highest a coach should be paid is 20 million, not 30 million or more.
If the coach can lead the team to the victory of trophies or an outstanding improvement in the performance of the club, then very high salaries are rational. Whereas in this case, despite leading Atlético Madrid to a quite good level, the consideration of 30 million or more as a salary seems extremely disproportionate, especially when compared to the top players who might be earning much more. For clubs like Atlético Madrid, which do not work according to the budget of Real Madrid or Barcelona, the allocation of so much onto one single person raises questions regarding their expenditure effectiveness. More so when the salary in question is mostly very far above what other coaches get, despite that they are also very successful. In summary, the burdens an extremely high salary places on it and not always reflecting results on the field may make a coach an important asset to a club.