People will hate to hear this but a centralized market board is one of the big reasons for how easy it is to control the market. Most games with an auction house, market board, etc. have these problems. WoW gets away with it only because there's so many players. From my experience games without a central trading location (ESO, UO, Mabinogi) all have player economies that gives everyone a chance to sell. Those games have a bigger focus on crafted items too, XIV's economy is pretty poor in comparison. 1.0 had a much better base for a good economy but it was too complicated for most people (and people didn't use market wards right).