the control system was what got everyone talking in the first place, but I don't think it lived up to its potential. Very few game used it to provide a unique experience, all the multiformat games that were on the wii were better on other formats, even after you disregard the weaker visuals. Wii sports sold the wii and as it stands I think that's a concept that's exhausted now. I don't think the wiimote really has any great momentum for it to sell another console now.
I think, in an ideal world Nintendo would produce a console on par graphically with the other 2, but with motion controls and their unique IPs, at a lower price than the other 2. If that was possible (and they sorted out their online infrastructure), they would be as untouchable in the home console market as the are in the handheld market.
In a way, they are taking a safer route with the switch, its a tablet with all the problems that come with tablet gaming removed, and nintendo IPs. That makes a hell of a lot more sense than trying to fix the wii/u situation and although it wont make great shakes in the gaming world, it'll provide a better version of an already established market.