A problem which plagues all artists: what do you do once you've established yourself? There are two main routes, and no matter which way you go, you will have detractors.
First, you can continue doing what made you successful in the first place, with subtle variations. This is the idea behind most procedural TV shows like "Law & Order," and while that's an interesting show and can be entertaining, there's only so much you variation to be found in between the primary events: crime, arrest, trial, verdict. People who dislike these types of art claim that a creator is one note, boring, afraid to try something new, and ultimately, not truly creative.
On the other hand, you can take whatever made you successful and push it out in new directions, or even do something completely different. This I would say is more common in music, where a band will transform itself and its sound over time. Look at the most popular rock band ever, The Beatles, as they transformed from well-groomed suit-clad British blokes singing about holding hands to long-haired bearded hippies singing about the glories of LSD. Of course, critics of this path say that you're abandoning what made you popular and by extension your original fan base, that you've "sold out" or weakened your product by not sticking to what people originally liked you for.
Personally, and I still hope I one day reach a point where I am faced with this dilemma, but while you are damned if you do and damned if you don't, I would choose the second option every time.