I agree that a graduated hierarchical system is best. A good model for designers would be the techniques used by modern game designers. Most modern games are

I agree that a graduated hierarchical system is best. A good model for designers would be the techniques used by modern game designers. Most modern games are extremely complex and have a graduated system in which you master one aspect before moving on to the next. If learning a program or OS can be done in a similar manner to learning a video game it might work. Personally I think the solution to the "hierarchical" problem is search. Apple has done a great job with the Spotlight tool. A similar "search" based function launcher might work well to provide access to features that beginning users don't care about but advanced users want.