I believe that De Rossi's Roma would stand more chance against Milan. They failed with Mourinho against them. They lost twice in their domestic league. However while there is good progress in Roma football I'm more expectant from them. Because above all else they have started to play an effective attacking-oriented game. 
This was what Roma needed. Mourinho was just placing obstacles ahead of Roma because of his boring defensive strategies. Roma aren't a good defense team. We must have all understood it so far. They need to play more attacking to balance themselves.
Milan are still a tough opponent but Roma have more chance to advance after some important changes made by De Rossi.
Indeed Jose Mourinho not success well such as Daniele De Rossi but he was build up AS Roma foundation after signing several important players and braveness for promoting some young players. Current AS Roma condition seems Daniele De Rossi just building up what have foundation made by Jose Mourinho, however although many controversial after sacking Jose Mourinho from his position but he was success give the first trophy for AS Roma by winning Conference League and lead to final stage in Europe League last season. This was what Roma needed. Mourinho was just placing obstacles ahead of Roma because of his boring defensive strategies. Roma aren't a good defense team. We must have all understood it so far. They need to play more attacking to balance themselves.
Milan are still a tough opponent but Roma have more chance to advance after some important changes made by De Rossi.
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.