"How about keeping the same controller just so we don't have to buy a new set of 4 every generation. There's no shame to saying, hey we have a good design here, maybe we should keep it for a little longer."
But they don't have a good design. Well not a universally useable one anyway. Sony has kept the same controller design which is nice for people not wanting to buy new controllers but it sucks because the original design needs refinement. It's the same way with Nintendo. I loved the SNES and N64 controllers but I'm glad they've gone beyond that. Controllers can always be refined and perfected and updating it with every console makes sense.
Plus aside from refinement there's still room for innovation. What if they included a motion sensor like the one used in Kirby's Tilt 'n' Tumble built right into the controller? This is on top of providing a standard flexible controller design. Suddenly, much like with the DS, the controller options open up without sacrificing classic game design. I think the DS should have had an analog stick but aside from that its greatest feature is its flexibility. Developers can still make traditional portable games like they could on the GBA but now they can also use the touchscreen and the mic. The flexibility gives the DS an edge.
I'm afraid Nintendo might do something too weird with the Rev but there is also the possibility of having incredible flexibility. Imagine if the controller had two analog sticks, a SNES sized d-pad, six digital face buttons, two analog triggers like the Cube, two digital triggers placed in front like the Cube Z button (but built more ergonomically), a start (& maybe select) button, built-in motion sensor, built-in rumble, standard wireless control with optional cords, and an slot for expansion like the N64 controller. Plus have the system come with a mouse, a keyboard, built-in broadband adapter, wireless connectivity with the DS, some sort of internal rewritable storage like a hard drive and Gamecube backwards compatibility with the Rev controllers using the same controller ports as the Cube and the same memory card slots.
That would provide tons of flexibility and potential gameplay innovation. Now realistically that could drive the console price up a little bit but virtually any genre including traditional PC genres like RTS could work. That's what I ideally would want to see Nintendo do with the Revolution. There's room to move in a new direction without disregarding what's already there.