They have that system in-place within Final Fantasy XI Online and while it works fine to combat the listing Fee's possible abuse and waste, they opted to completely hide the Sale price altogether, so you must make a Bid usually going by the Price History of an item, repeated Bids are needed to win an item (Buy) usually as you never know if what you're bidding on is 1 Gil or 1,000.000 or more, for example.

They would need to do this here in my opinion if they used your request, if they didn't, it would be even easier to control the markets as many players would opt to not compete at all and maybe even leave items up at higher prices for longer periods of time due to the listing fee, while power-sellers and possibly Bots don't care about losing money in "fee wars" (taking down item and relisting over and over until they scare off potential competition or drain the competitions purse/wallet enough that they leave).

I would prefer the Final Fantasy XI Online Auction House over this games current Market Board setup.

Or leave it as it current is.