In a system with direct trading, you only need to know the relative value of two items to create a good trade. One is slightly better ? Put a few dozen k in.
Nobody does this. Everyone assumes their item is relatively more valuable, e.g. Dach asking for 55k no matter what item he requests.
Your reasoning is innaccurate as hell. Listing standing offers is only a way to show what nobody accepts.
Then why do we have this system? Nobody accepts the offers because they are obviously unfair but most of the time it is too difficult to figure out how to arrange a fair trade.
Imagine you are a 2h swordsman, and say you have a +3 GGS and want a shiny +3 SoW instead. Thing is, you use that +3 GGS because it is kinda good, you just want a +3 Sow because it is better. You don't want to be unable to use an heirloomed sword for an indefinite amount of time just because you wanted to change.
Current system: You see an offer of +3 SOW. He wants a +3 GGS + 100k. You think that's unfair so you post an offer of +3 GGS for +3 SOW. Nobody accepts it because like our in-house expert/troll Falka points out: "first rule of the market - to rule them all - make your own offers." What can you do? Click through a dozen links to determine if you've just been unlucky or maybe your idea of relative value is not so accurate?
The bottom line is, having to do two trades instead of one for something as basic as exchanging items is not acceptable.
Every comment you have made has ignored any possible positive outcome from a gold-only system, despite my evidence that only 4.3% of people are trying to make the kind of offers you keep talking about. That 4.3% is not science so take it with a grain of salt, but don't act like ridiculous offers are not the norm.
Yes, my proposal negatively impacts the 0.001% of trades which involve a guy who:
A - loves his item,
B - but still wants to trade it (for some reason. . . )
C - and can't stand not having a replacement heirloom immediately.
I do not propose my system as a perfect solution., but your entire criticism of a gold-only system is premised on being unable to use an heirloom which you
do not want for a few hours or days. And you ignore every possible advantage of a gold-only system. I list several cons in the OP. I wish you would have the decency to do the same and look at both sides of the argument instead of just finding one problem and harping on it for the sake of maintaining your tax-free trading post.