I would love a player market system similar to EVE or POTBS but bear in mind that this is not a "money generation" system.
cRPG's market is purely for bringing money into the game world.
EVE has a tremendous trading market but to actually bring money into the world you have to go out and kill NPCs. NPCs drop money, and missions give you money and that's your money inflow into the game, which you can then bring to the trading market.
If we turned the cRPG market system into a crafting system that's great, but then we need a new way to bring in money.