We are going to see a different champion this season 100% because of Sevilla's not making it here at least. This is good news to me though while respecting Sevilla's outstanding number of titles in the recent 10 years here. Maybe it is time for Mourinho to do this work with Roma this year. They were so close in the last one but lost the chance to Sevilla.
But there are huge threats such as Leverkusen and Liverpool. With the current strength of their squad and inconsistencies I don't know whether Roma can repeat the same level of achievement at least.
They might need luck on their side a little on draws as of now maybe.

Liverpool, Milan, Roma, Galatasaray, Braga and Benfica are the teams that come to my mind with a possibility of championship. These teams will try hard to get to the finals. Liverpool will be the first team in the final, barring any unlucky events. If there are no draw problems, the other team could be Milan. This year there is a European league full of strong teams. Of course, we should not forget Bayer Leverkusen. They are also championship candidates.
This year's Premier League has a number of teams who are performing brilliantly. The Liverpool team is at the top of the Premier League table. The Leverkusen team is at the top of the table in the Bundesliga. Sporting team is top of Liga Portugal table, Young Boys is top of Swiss Super League table and Galatasaray is top of Super Lig table. Also the performance of the Milan team is quite good. No team can be underestimated here. However, Liverpool, Leverkusen, Milan and Roma seem to be the most qualified for the semi-finals. However, the performance of Galatasray, Sporting and Young Boys teams is also very good. So the Europa League will be very competitive this season.