I think that there was a lot geared towards his success from day one. Much as like with Everton, he came into a team that had great players and star individuals. With us he also came into an environment and team that were brilliantly drilled and set up. Hence with both clubs he had a decent first season, but then when he's had to continue a task and 'make it his own' he's had some serious struggles, and fallen out with people left, right and centre, whilst playing golf.
I don't think he's a terrible manager by any stretch, but I really don't think he's any more than average (or any better than Puel/Pellegrino etc). I wouldn't want him back, even if we were struggling.