For me top annoyances.
1. No BBS system, where I could advertise, I can make this and that, costs that much, if you like my prices contact me.
2. No bartering system, I have this and I would like to exchange for that (those) items.
3. No items listing scrolling, what is with this pages clicking? Obviously BW employees not playing game.
Current GTN is typical auction house, like in any MMO and it is so out dated. Come on BW, something new please, GTN is just copying other games AH.
And because no BBS or bartering GTN is a mess, like mentioned above, you have click through so many pages, where just 1 item of stackable goods is listed.
GTN is the most basic crap of auction house ya can find. myself i love the market of EQ2 or the open market on EVE. but think the market of EQ2 would fit this game best.