If Nintendo's idea is so easy to copy, Sony and Microsoft will copy it long before the end of the generation anyway. Analog controllers became standard in the Playstation's lifetime, even though it started out with a plain old d-pad controller. What did hiding the N64 controller do for Nintendo? Not much. Choosing carts (even though I like them) probably had a bigger effect on Nintendo 64 than having analog control.
Nintendo's advantage lies in quality games that take advantage of the new interface. Analog control wouldn't have meant much for the N64 if it weren't for the fact that Super Mario 64, Pilotwings, and Wave Race all made great use of it. As did Cruis'n USA, Mario Kart, Turok and Blast Corps - all released in the first 6 months of the system's lifespan.
Maybe Nintendo should show off the new interface and a simple demonstration of what it can do for a traditional game (Super Smash Bros or Metroid Prime 3). Then leave us with some game footage and the idea that there are even cooler uses coming for the controller/interface. The whole "interface" thing could have something to do with this as well. It's possible Nintendo can reveal the controller and some revolutionary parts of the system without revealing everything.
Whatever the company does, the basic idea is to give people enough info to get excited now instead of 8 months from now.