They were disinterested in starting anew for HoI3 so this would hardly be a surprise.
I think you don't understand what motivates creative people, if you expect modders to cheer at the idea of re-implementing something they once created. They'll only do it if HoI4 really offers exciting new facets to the KR experience, so that it would not be a mind-numbing re-implementation effort but a creation of something new.
I wouldn't count on it... KR was really very fleshed out and thrived on the "railroaded" way events were written during pre-Clausewitz times. It was a different time, and those games were made a different spirit. The whole idea where you replace event chains by abstract, symbolic stuff like "influencing" people into the corner of a triangle (like in HoI3) or "sphering" them (like in Vic2) is really alien to the old mindset. Those systems are so abstract, they throttle the creativity and make people loath to try and reinvent them for a new mod setting. Like I said I would cheer if they port it over, but I wouldn't count on it.