Next season it is still very possible to expect more surprises in the Europa League because besides there are many big teams who will compete there, of course there are many other teams who are not favorites to win the title but those teams can beat big teams like what happened last season when Liverpool lost in the Europa League. And usually teams like Sevilla or others who are not too focused on the domestic league will put their focus more on the Europa League for a trophy, but as you said in the Europa League next season nothing is easy to achieve for any team except for the team that really has great ability.
The Liverpool incident last season has turned out an eye opener to many others that winning the Europa is something any team other than the bigger teams can do, interestingly this is one of the rare occasions as Atlanta isn't a regular winner of the Europa, they even made a record amongst their Italian mates winning the Europa last season. Sevilla didn't qualify for the Europa so I think there's a mix-up with your reference. Although Sevilla happens to have the most Europa trophy and if they were to be in the league this season with their experience I believe the would have been able to do something interesting.