I have serious doubts it ll be as big as the Wii was.
I think theres two kinds of views of it:
1) its a cool handheld (powerfull handheld) that can also play on your tv (expensive handheld).
2) its a homeconsole (really weak) and its overpriced for its hardware (competitors x3 power & cheaper)
The 2nd view point seems to be pretty popular on youtube.
I dont think they ll do 100m with the switch.