I think he peaked at the Inter job. Rather than evolving he just stuck at the time when he knocked barca out. In most of his interviews about his past achievements he always cherishes the 1-0 loss which led to knocking out Barca. He loved it so much that he adopted that method as the sole method of success. The first sign of that was when athletico knocked chelsea out when he was parking the bus for no reaaon. Yes he won the title but he again became defensive after the 5-3 defeat to spurs that season.And especially at Inter, where he took over a team that, while successful domestic, had consistently failed to get past the round of 16 in the CL. Even the team United knocked out in 2008-09 with Jose as manager was half the team he assembled and managed to the treble the next year.
Transfers were essential, especially the Zlatan transfer, but he built a team that was well drilled, was difficult to break down, and was willing to run through a wall for Jose. He also helped revived Sneijder's career, who was a bit of a failure at Real, and even built his team around either outcasts or relatively low-key signings like Lucio, Pandev and Thiago Motta.
Looking back, he was only "lucky" in that he had a couple key core players when he arrived at Inter, including Zanetti and Cambiasso, and they had a relatively settled defense, but he also built a great team at Inter and many of the key signings were made during his tenure. He rebuilt their entire front line, he got rid of a lot of deadwood and he set up his midfield to allow Sneijder to flourish.
He probably never should have left Inter in retrospect, but it is obviously difficult to turn down Real Madrid.
I remember during his time here, I always wondered why is he complicating things when there is no need. The best example is the celta vigo second leg game. Celta vigo were 10th or below in La Liga when we were facing them but for some reason Jose still was cautious in his approach and if not for Geudetti's (or however he is spelled) simple miss we would have been done.
He needs to go away from english football for good. Just manage some club in serie a or Portuguese league. He may have a better chance of doing something relevant there.