Roma must have a very good defensive line. They have only 1 defeat at the moment and I can say that they went well.
They need to improve both. In defense, improve it stronger to reduce conceded goals. In offense, they must improve the conversion rate from chances, expected goals to real goals. They must achieve such improvements if they want to not only end in top four but also to win Scudetto.
As Roma need consistency and mental confidence and most importantly need additional players in the midfield and defenders because practically pelegrini, Cristiano has no replacement, defender is not too good if Mancini is injured there is no replacement either.
If the opposing team has good finishing touch quality, A Roma has already lost. That's why you can end up losing to Udinese.