The reason teams in Europa League can't sustain a title challenge is because they're always playing last on the Premier League weekend. Other teams in Champions League end up playing earlier than them so inevitably are always ahead and the Europa guys never get to put points on the board first to put any kind of pressure on the rest ... they're always chasing ...
Other than that there's no difference between Wed-Sat or Thu-Sun in terms of time in between. Take our example this very week for example we are flying so far away for Wednesday night game but will be playing Saturday first game on next weekend as well. Drawback: Yes less rest-recovery-prep time ... but advantage, we play first ... win it and then see how others like with that pressure ...
I think West Ham can finish above both Leicester and Manchester United for that reason alone, they have full clear week all the way and other two are tied down Thursday nights and always will play later on weekends. Which is why I said in the Liverpool pre-match as well I don't even consider Leicester or United as title rivals.
More on that in West Ham Pre-Match Thread ... I should get writing that now, as would have to post soon after the game tonight ...