If you look at Nintendos home console history its - inovate, play safe, innovate, play safe, etc.
NES - gave us the D-Pad
SNES - gave us amazing detail sprites on the game
N64 - gave us analogue stick
GC - gave us more processing power and just nicer looking games
Wii - gave us a new controller with MS+P
The next console has already been confirmed to have 3.2Ghtz multi threaded processing chip. As stated by ATi or some chip manufacturer rightwhen wii launched. So HD graphics plus Wiimote. Wii HD.