Every manager has difference strategies, under Daniele De Rossi make difference game play with AS Roma more active for offensive than Jose Mourinho era prefer for full defensive.
Indeed, we know that the strategy adopted by Mourinho is more defensive, especially if the opponent they are facing is much stronger, they will defend completely and only rely on counter attacks. Meanwhile, in the De Rossi era, AS Roma were more daring in attacking and the results were quite satisfying because there were good changes that they could show.
With a more open strategy like that, it is possible that they will have a greater chance of winning the match, and De Rossi dared to do that. What De Rossi has shown with AS Roma currently looks good and hopefully they can maintain it, because it is not easy to change the style of play, it requires a process.
I agree with what you said, De Rossi has brought renewal to Roma overall style of play today, which is very different from when Mourinho was head coach. De Rossi managed to find a strategy that suited the depth of the squad he had, so that he could bring out the best potential from each of his players. He understands the club well thanks to his experience serving there.
Mourinho tactics were too defensive, not balanced with a solid defensive line, therefore they failed to become a strong team. Mourinho hopes to implement a defensive strategy at Roma, where he has had success when coaching Inter and Chelsea. There Mourinho had a number of the best defenders in his lineup, while in Rome everything was different, which is why Mourinho seemed to fail.
Meanwhile, De Rossi saw this weakness and made strategic changes, attacking more aggressively and dominating possession of the ball. This has proven to make it easier for Roma to win matches, and all of its players can more freely unleash their full potential. De Rossi managed to see Roma weaknesses, then turned them into strengths so that Roma managed to appear consistent.