The reason why English clubs have not been doing well in the Europa League is that they have been tactically good enough when going to Europe for some times now and so they got knocked out when it gets to the knockout stages of the competition, last season I can say that it was even due to luck that both Manchester United and Tottenham got to the finals this is because other teams too where not that informed
This season might be different from last season, where teams from leagues other than the Premier League weren't as competitive. However, this season seems to be different because English teams will also try to dominate the Europa League this season, although I personally have more confidence in Italian teams like AS Roma and others. I hope that in this Europa League season, one English team can reach the final, and the other will be from another league.
More teams from the English Premier League qualify for the European League and the English Premier League teams always do well in this European League. Last season, the semi-finals and finals as well as the European League title were everywhere, but the English Premier League teams dominated. The teams that played in the European League last season will play in the European League next season as well, so the results are unlikely to be different. There are some teams in the Italian League who perform well in some matches but their performance is not consistent. In all these tournaments, each team's performance should be consistent.
Last season, Tottenham won the European League title, in the new season they are performing quite well in the Premier League, so this team can be trusted again to perform well next season as well.