I hate to be so gloomy about these glimmers of news, but I'm very much reminded of
Samurai Shodown 2 -> 3
and
Fatal Fury Special -> 3
In both cases, SNK had a hit on their hands. A fighting game that was far and away more successful than any other game were producing at the time. But instead of playing it safe and giving people more of what they wanted, they went back to the drawing board and completely remade the graphics and reworked the fighting engines.
It didn't work. People stuck with the game they preferred, and the player base was fractured.
KOF XIII has been their biggest fighter in twenty years. This is NOT the time to do something different. Make a few new characters, new stages, give existing characters new moves, and release it as KOF XIV.
Some people call this "milking" the franchise, but it's actually supporting the scene.