Simeone thinking has definitely stop atleti from winning 1 CL.
But getting to 2 finals, losing one on Penalties.
I don't know how many SF.
2 league titles and pushing the top 2 in La Liga.
You can't talk too badly about him.
As I have explained in the past, for me it's
1) Simeone 2011-2016 or so
2) Simeone post-2016
early Simeone deserves huge credit for raising so much the floor of a club like Atletico and doing wonders against the big boys on a tiny budget, despite his ultra-defensive ugly football. Deserved also the 2014 CL IMO (not the 2016 one, where Pep's bayern should have won it)
But after that lost 2016 final, Simeone started recycling himself and his old ideas without any innovation, and that was especially at a time where football was changing at fast pace: Klopp ball, Pep's evolution at city, most teams introducing pressing and intensity, etc.
He could not keep up with the changes, he never renewed himself and his ideas, so he became a caricature of his old self, and turned Atletico into Pathetico! Since then he only won the 2021 LL title by pure luck [a season where Madrid were terrible and Barca were in huge reconstruction (and still Barca under Koeman were better and deserved to win it) and both handed themselves the title to Simeone in the last 5-6 matchdays]
He is keeping his team back and bottom line he is keeping the club back. Atleti hierarchy should have grown a pair, thanked him for what he did for them, and should have gone for a top coach with a mind geared according to the modern game.