One season is hardly enough to judge Mourinho's ability as a manager. So he was on a rut at Chelsea last year, so what? He's suddenly an ineffective manager now? That kind of thinking is too simplistic.
One season? Do you think I judging him without any good reason? I'm a madridista, and I saw what he did for Real Madrid with his sensational attitude. Even he was fired twice in Chelsea.
Did Mourinho tell you on what strategy he will use on MU next season? No, right? He might change his strategy anytime he want, so you cant judge it before you see the strategy.
He is a typical of coach who has limited amount of strategy. If his strategy cant work in a match, then in next matches he wont make any new one, and prefer to make a little changing on his current strategy.
Before became a Man United coach, Louis van Gaal was an extraordinary coach with many successes on his previous teams. And I still remember Man United fans were very optimistic on him after club announced LvG as their new coach. There is no different situation now, with many great achievements by Mourinho, still there is no guarantee he will make Man United rise again.
Again, your comment about Mourinho's strategy 'can't work in the EPL' ever again is simplistic. I mean who are we to judge that? We are mere spectators in the game and far from being experts.