There were people using the technology that powers the motion controls utilized by the Wii, years before people even speculated that the Wii was gimmicky.
old tech. A new use. A new application. A new Industry. A new Audience. New Marketing. (A new Generation?)
It's all just semantics, yeah, but this is how most people and dictionaries seem to define "gimmick". To reference a sort of .."tacked-on" feature. And it's easy to imagine someone "tacking on" 3D visuals, or ..touch screen controls, to a design that's otherwise just fine. But was it made better? For just me? For you? ...there are a thousand ways to fork this now, from here, and end up loving and/or hating 3d stuff...