Manchester united has the qualities of winning the europa league but it is not still certain becoming the champion of the league will go to them. Anything can happen along the line, football can not be predicted and their other good teams that are good to win the europa league too.
From Liverpool game there's been this change of mindset, I don't really know if the squad might be fatigued currently or something but they really need to put themselves United and together. The draw against Southampton at Old Trafford was welcomed as a fan.
Yes they have huge potentials even with a tactically sound coach to lead and guide them to win games.
Arsenal are also another favorites to win the Europa League Competition, Juventus likewise and also Sevilla who have dominated over the years. Arsenal should focus on the premier league is they know whats better for them. I can't see them not winning the Premier League.