Imo the second analog nub isn't necessary for the Japanese audience, look how great is doing without it, developers don't need it (the only game I can think of that will really benefit from it is Monster Hunter), but from a western perspective I think most of them need it, either for making a FPS or having an easier way to control the camera and I think that's the main reason we won't see much third-party support from western developers anytime soon.
Nintendo and PC gamer