Simeone struggles quite badly to reinvent his team and still relies on the same core (Godin, Griezmann, Costa, Filipe Luis, Koke, Juanfran) with the additiona of some youngsters, who had a lot of time to get used to him (Saul, Thomas, Correa, Gimenez). Most of the established players, that he bought, didn't have a lasting impact: (Alderweireld), Mandzukic, Jackson, Vietto, Carrasco, Kranevitter, Cerci, Gameiro, Gaitan, Vrsaliko, Vitolo and Gelson Martins (he is new, but he'll fail). He struggles to adapt his tactics to his players. When he buys a new player he expects them to be a like-for-like replacement for someone else. Yet no player is exactly the same and this severly limits new players.
The character of the current United team is very different to the one of Atletico and I doubt that he is flexible enough to change his approach. There are very few players in this team, that would be able to do what he asks them to. Yet his transfer history is extremely mediocre even if you'd want him to build a new team from scratch. Additionally there is a huge risk that his own personality/culture would rub people (= his players, the fans, the press, team team around him) the wrong way.
So, no, Simeone is not the right man for United. If he leaves Atletico, he should go to Italy and try to re-build one of the fallen gigants of Italien football. He could be perfect for that, because he'd be the underdog again.