Of course, each coach will contribute to the team, but each coach has a different strategy on the field. Mourinho always builds a game from defense, he is a representative of Portuguese football, they are accustomed to this, but the point is that this is no longer as effective now as in the old days, now attacking football brings the best results, and such matches are definitely always more interesting to watch. Agree, with the arrival of De Rossi, Roma's matches have become more interesting.
We picks interests in matches and also in elite teams. José Mourinho was a blessing to AS Roma in his first season, he set standards for the club which they're enjoying till this present day. Mourinho lifted major trophies for AS Roma and he's always getting closer to enter the top race when he was incharge unfortunately, he got sacked when AS Roma was having one of these downtime in football. However the new coach, Daniele De Rossi is tactical and have shown samples of taking the club to good phases in the system.
Every coach has a different strategy and indeed we cannot judge from one point alone, José Mourinho has proven that he is a pretty good coach when playing on the European stage and that has been proven since he coached Roma but regarding Roma's inconsistent performance at The domestic league I think is a different thing.
And De Rossi has also proven that he can make Roma better, but he has not proven that he can do better on the European stage than what José Mourinho has done.