I feel like these two FG companies have quite a few similarities with how some of their franchises are, with Tekken / King of Fighters and Soul Calibur / Samurai Shodown being pairs with legit similarities when it comes to fighting styles and in some cases, a few characters.
With Geese entering the fray in Tekken 7, I would be pretty excited to see a full-on crossover between Namco and SNK - part of it is for the sake of including some obscure characters, much like in Marvel vs. Capcom, and I gotta say, it could probably be the only chance that KOF Maximum Impact fans could get at seeing characters from that game again. Plus, it could help SNK get closer to its former glory, after the start of its resurgency with KOF XIV, with a crossover close to the level of how Capcom vs. SNK was.