While it is true that Roma got better, hell even MUCH better, after Ranieri took charge but could you say that they are good enough to win the whole thing? I agree that they are better, but I am not entirely sure if they are better than everyone else. I do not see them winning the title this year, there is a very slim chance of that happening. We should not expect them to be that great neither, that's just way too high expectations and makes their life harder as well.
Anything close to quarter finals is more than enough for them, and at the league if they finish within top ten that is enough. Do not expect them to do better than that and if they do better than Roma fans can be happy, but if they are not doing that, then it's fine.
Although Roma have gotten better since Ranieri took over there is no chance for them to win it all because the competition is so tough with a few points behind that will make it difficult for Roma to achieve anything. To win the title I think it is difficult for Roma to achieve this season because they don't get many chances and the number of players they have have not shown their best qualities.
To get to the semi-finals is also not easy because the competition will be much tougher and Roma itself must try to do its best by competing with several other strong teams. However, getting to the quarter-finals would be much better and Roma must fight for it this season.