I like the Gamepad, but it's hard to argue the general public's response to it has been colder than ice water. No one cares about it, and worse it's apparently adding like $100 to the cost of the console (according to Iwata himself).
It's not a bad idea per se, but making it part of the console as a standard IMO probably was. They could've just bundled it separately with Nintendo Land, like the Balance Board and Wii Fit and still let some people get some enjoyment out of it that way.
If they were going to make a console around this concept, then IMO it shouldn't have been part of the "Wii" brand at all. Make a new brand for it, keep the Wii as a budget motion gaming brand.