There is absolutely NO credible reason that the respawn timers for land kings need to be at 21-24 hours. Not then, not now, and certainly not in the future. I could care less that the Black Belt is the single-best equipment a Monk can have, There is no logical purpose for imposing artificial competition for the items required for the quest (unless you're one of those "hardcore" trolls who make up any excuse for anything that keep non-"hardcore" types from getting these quests done).
The KSNM99 alternative, I'm sorry to say, doesn't cut it. Making the drop rate less than 90% renders it a half-measure and a cowardly display of pandering to career endgamers who fear that their cottage industry, extortion of those who need the items, are under threat.
What needs to happen, and soon, is the reduction of NQ land kings' respawn time to no more than 4 hours. Apart from providing people from every region more chances at the Black Belt quest items, it strips HNM shells of their power to charge outrageous prices for the chance to lot for them.