Success in European cups is a separate topic, besides now it is the first stage of the playoffs, so it is too early to judge. The question of competitiveness is the question of the interest of the league. If we already know the winner of first and second place (as in the Bundesliga or the Premier League now), then there is not much interest in watching the games, as they turn into local confrontations.
I think the goal difference from Arsenal shows they already likely made it to the next stage while Aston Villa likely also and tonight we might know the fate of Liverpool in the Champions League.
I think the success of these teams including Chelsea and Manchester United in conference and Europa League respectively are important. While the competitiveness on the EPL is really interesting top teams are somehow weary of mid or lower teams because they can mess things up for them if they are not serious, the top four race is now more fierce than the title race and we shall see who may likely may it to the top four soon.