I guess the hardware has been fine for their art style or whatever, but you cant keep using gimmicky controllers as your primary input device. The market has shown they do not want that shit.
It kind of depends on what you define as a gimmick.
The Wii motes to me were a gimmick. I hated those things. I don't want to move my damn self around when playing games, fuck me that is what real exercise is for. I don't understand why that shit was so beloved.
The Wii U gamepad isn't a gimmick to me ---- I actually really like the thing, and dislike it equally. It obviously is great for Mario Maker like CB pointed out and like what I said earlier, it serves as a nice extension if your console isn't in same room. I really doubt most people have the same kind of set up I have though.
But man, that thing has the worst battery life ever, and I just hate having more peripherals, more wires, more things to charge, etc. And there is some stuff in gameplay that requires the gamepad---like, what the fuck.