Of the four top teams that I mentioned, only Roma will return to the European league and the rest will compete on the bigger stage of the Champions League. Is it possible that the underdog team will surprise again next season? remembering that everything is possible after seeing Atalanta this season and of course we won't see Sevilla either because they were knocked out last season and in the domestic league they finished in the bottom position. 
Atalanta unexpectedly won the Europa League title this season. However, this team gave a lot of effort to win the Europa League title. The Atalanta team was not the favorite for the Europa League title. But it was not a weak team either. Atalanta qualified for the final with a good performance, and the team also performed well in the final match.
No word yet on which team will win the title next season. However, in every season of the Europa League, Roma team is considered as the favorite to win the title. And the Roma team also gives full effort to win the Europa League title. It remains to be seen how Roma will perform with De Rossi next season.
I think it's not just Roma that will remain a threat in the European league, considering that there will be other strong clubs dropping out of the Champions League and that will increase the intensity of the competition, making it even more exciting. I think next season's European League will still present interesting things and maybe more than just the favorite teams, we will see the same thing as this season.