I think F1 has certainly changed a lot, back than Michael Schumacher can do whatever he wants to the car and test it whenever he wants. Now its teams make parts and you go out and drive, you cant even have the weight distribution that you desired or the "special tyres" you wanted.
I believe that so much of his success was down to how he manages his resources, and since today's F1 is more about handling your resources its hard for him to adapt the the situation. I think he is doing alot better compared to last year, but 1 thing still stands true is the fact that he is not out performing the car, I think that is down to driving styles, where as in the past he always had the preferences that he wanted, even if the car is low on downforce he is comfortable in the car and thats why he was able to push hard in those days.