A change in design? Every manufacturer making a successful smart phone right now is using the same design, with varying degrees of screen size...there's no way Apple is going to make a behemoth iPhone, it's just not going to happen, the elongated screen is your change (as is expected from Apple, who took an unorthodox route and it will prove to be very successful, just watch).
I don't think it's fair to say that RIMM got stuck either, because honestly, they tried pretty much everything they possibly could to stay relevant, they took the favorite devices and made them bigger and refreshed them, they took on the touch screen, they offered a flip phone...if there is one thing about the Blackberry lineup that i can say, it was definitely diverse as far as design goes, and "stuck" isn't something i'd personally label it as. Their issue was the idea that people found the keyboard as a necessity, and only made one poor attempt at changing that line of thinking with the Storm (which was still not quite on the level since it "clicked", giving the impression of a keyboard like input).