Software like Virtual DJ and DJay Pro AI come with fully-functional official mappings for a variety of controllers out of the box. They consistently work better than whatever .tsi file I can find online for Traktor, and the selections in Traktor are laughably out-of-date with a variety of controllers listed that haven't been made in years, and nothing you can even buy currently.
This seems like pretty low-hanging fruit to significantly improve the product. Can't y'all just buy a few Rane, Reloop, Pioneer, and other mixers/controllers, map them well, and have them properly set up out-of-the-box? Right now NI doesn't even sell a DJ Mixer, if you want to do a DVS set up you need to go to the used market for an old NI model. The easiest solution really is for NI just to admit they aren't going to release a proper mixer and do what I imagine is a week of work to support the most popular hardware.