The Headless Horseman spawn time is currently set at 6 hours. As it is one of the best ways to level up at higher levels, many classes rely on it as a form of training. Having NX as a drop means it is one of, if not the most, farmed area bosses in the game. Tons of high-level players that may not be able to solo Bigfoot simply rely on killing the headless horseman instead. I understand that he spawns on a ton of maps, but having had to try and find one for the better part of a month, I rarely ever come across one. I believe it is due to the NX farmers using it as a main mob to kill to acquire a lot of NX quickly. If we can find a way to either nerf the amount of NX he gives or boost the spawn time, I think more and more people will benefit from the EXP and be less inclined to leech. Therefore, you enjoy the game a bit more rather than spending vast amounts of hard-to-acquire mesos on leech.