I go back to my TKD days on this. I agree that usually kumite improves when started early in the process.The key being that kihon must be a priority or the kumite will be very sloppy. There should be an emphasis on structure of the strikes and time spent on footwork.Too often I've seen people in kumite that weren't grounded very well in the basics. They get out there and pound it out.Some are successful just on sheer strength. They over power their opponent.This will take you just so far.The key for the less imposing fighter is to have better technique. This comes from the kihon practice.