The advantage of asynchronous buying and selling is that regardless of whether you're online or offline, the transactions you are willing to make are available. So for sellers, this means that even if we're not around to physically complete a sale of a product, a buyer can choose between our offers and our competitors' offers. The only advantage to camping the auction house is that the campers can change their offers more often.
What Blizzard didn't take into account when designing the auction system is that there is just as much fierce competition among buyers as there is sellers. Right now, if someone needs a lot of Saronite Ore, they have to either be the first one to see a well priced auction, or they have to be online to see someone advertising in trade. This means that the buyers who do the best (have access to the most mats at the best prices) are the ones who can afford to camp the auction house and trade chat.
Of course, we all go around the system when we can. We'll use the "snatch search" feature of auctioneer, as well as ask farmers to send their mats to us cash on delivery. Neither of these solutions are ideal, however. Snatch saves us time, but only lets us buy what's already on sale, and many farmers don't farm nearly enough to bother adding an auctioneer to their already cramped friend's list.
Open orders would solve this problem. Whether the farmer is high volume or casual, if they had the ability to go to a city and see all the demand for their wares, they would be happier, and the auctioneers who end up buying their stuff wouldn't have to spend as much time as in the current system.
The way I imagine this system is that it would still cost the seller money to fill an order, so that sellers wouldn't be biased against listing auctions. Each open order would have a maximum volume and a minimum quantity.
For example, I buy a lot of Cobalt Ore. Instead of spending a few minutes as often as I can spare the time checking the AH for it, I decide to post an open order. Since I only have time to process 40 stacks this weekend, my open order is for 800 ore at 1.5g each, with a minimum quantity of 1. I could choose a higher minimum quantity if I want, but I don't want to miss out on the people leveling mining with small stocks. Now, as miners come onto the AH, they would be able to choose between selling directly to me for a guaranteed sale, or trying to sell their stock for more as an auction.
Downsides? What downsides?
This would potentially reduce the amount of stock available immediately for casual buyers, but to be fair, every time I log in, I do the same thing by emptying the auction house of both factions of all the cobalt I can get my hands on. This system would actually go a fairly long way toward stabilizing prices, since people buying in volume who can afford to wait are no longer emptying the AH.
It would also be good because farmers would be able to decide what to farm based on real current demand, instead of just guessing based on what they remember selling. If a miner wants to decide between Cobalt Ore and Saronite Ore, all they would do is figure out how much they can farm in an hour, and see what kind of demand there is for each. Right now, the only information they can use to decide is information about the market last time they sold ore.
Being an auctioneer is like being able to print money. Or gold, as it were. Wait, that doesn't make sense... you can print on gold, but you can't print gold. That would be closer to transmutation? I can transmute titanium, but that's only worth it if the price of saronite is low enough to justify the time spent making it. I need some sort of analogy here. Whatever, I'll figure it out later. Making gold? Every week, Gold Capped will teach you the tricks of the trade. From setting up your auction addons and user interface, to cross faction arbitrage, to learning how to use your tradeskills.