Although Chelsea strolled the league last season, the second half of it they didn't play particularly well - they tended to grind out victories rather than outplay other teams. Fabregas and Costa started the season superbly but dropped off badly from January onwards leaving a lot of the onus on Hazard for creativity and Matic to protect the backline.
Mourinho tends to like small squads which has the advantage of making teamwork instinctive but can lead to burn out, predictability and complacency among the players. He tried to address some of the burnout by having a late and reasonably relaxed preseason but, as we found out to our cost last year, that can leave the players sluggish in the initial matches. Think they are missing Oscar, he does a lot of pressing work high up the pitch which offers protection to the midfield and defence.
Chelsea had an odd transfer policy this summer with Pedro being the only one who looks likely to occupy a first team spot and quite a few of the players didn't get the benefit of any preseason with their new teammates.
There also seems to be internal issues like the very public spat over the medical staff, all clubs have such things but usually not a good sign when they are so visible.
Mourinho isn't used to being at a club over several seasons and he usually starts off his seasons fast and the defends from the front - groing to be interesting to see how he handles it.
