I see a good number of people who want to see an auction house added to the game. I disagree with this.
Like the title says, if the market ward system truly wasn't working out, why is it so full all of the time?
Remember back before the search function and the ordering of wards into separate categories? Yeah, the wards were mostly empty and people did the majority of their selling on their personal bazaars. It's because the wards were awful and didn't serve the function they were intended to serve.
Now, the wards work properly: items can be found by category and searched for within the ward. It's a simple matter to find the item you're looking for (it'd be nice to be able to search globally and see where items are, but it's not a deal-breaker).
My experiences with AHs in MMOs are very often negative. You put an item up and a minute later, someone undercuts you and the item doesn't sell unless you then undercut them, losing your listing fee in the process. In addition, the retainer system is what allows us to place items for repair overnight without leaving your computer on the entire time so your character can sit in a busy area.
I've been having FANTASTIC success with the market ward system. It doesn't matter what I'm selling: cloth and fiber, jewelry, tradecrafting tools, etc. I put one of my retainers in the appropriate ward and that stuff SELLS.
Again, look at how full the wards are right now. The system IS working, and I frankly think ditching it for an AH that invites RMT to move right in and run the economy is a terrible idea.