Uh, except that if I now make a topic in the General Twink Section called; WTS <x> and <y> it will get more views than anything in the "trade section".
I get that you want trustworthy traders, but basically you push out 999900 legit traders (who are looking for specific items across different WoW-sites, remember this isn't the only WoW-site where people can sell items) to keep out 100 scammers, which are recognizable only by their user name (or maybe their IP).
I don't have a better solution I'm afraid, but I would prefer the open forums over closed forums just for the chance to sell some items. I think people can take responsibility themselves and take their own precaution to avoid being scammed.