I would prefer two different options than a WTB/WTS/Services split:
Make a robust in game player-trade system similar to what SWG has implemented. That system works very well for a player driven economy and its totally in game.
If that isn't possible, then split the auctions into categories based on the level of the item:
- Atlantean Basic Market
- Atlantean Advanced Market
- Atlantean Superior Market
- Rimor Basic Market
- Rimor Advanced Market
- Rimor Superior Market
As a low level player, I've given up on using the market forums as its very difficult to find anything I can use, and even harder to sell anything I gather. And when I try to sell low level stuff in the 1-50 shopping channel in game, I get high level characters sending me tells complaining that the "junk" I'm offering (nanos available in stores at approximately 80% of the store price) is just spam.