A long time ago I read a good thing about balancing audience expectations between the familiar and the original, best explained by an analogy. If you go see a James Bond movie, you have certain expectations based on decades of earlier James Bond movies: you expect action, suspense, badassery, gadgets, villains, etc. If you don't get those, you will likely be disappointed. OTOH, if the movie sticks TOO closely to the formula, you will be just as disappointed; when you see a new James Bond movies you expect all those plot elements to get mixed up in new and interesting ways, with some sort of clever twist.
That's the fine line that Wizards has to walk with their D&D products. They can't JUST release a rehash of what has come before, or people will be like, "been there, done that." If they release something totally original, people will be like "WTF is this thing??? I wanted D&D!" Even if Wizards walks that line perfectly there will still be individual members of the audience who feel one way or the other, based on individual preference for familiar vs. original.
