There's no doubt Chelsea and Man City will improve next season, I think Mourinho takes a season or so to get the right players and the right mentality in his players, in his 2nd second you can usually see a vast improvement.
Pellegrini too will improve things, he's only been with the players a few months and hasn't stamped his authority yet, he's a very good manager though you only need to look at his record and how he's done at the clubs he's been at.