There's nothing wrong with the auction system.
I would use it for things that I'm unsure of the value of, or things that don't commonly sell and I just want to get rid of it, e.g., +1 Light Lance or +2 Throwing Dagger or something like that, where I might well be happy with something under the normal value.
I also suspect it's going to be good for selling heirloom points.
It's also slightly faster than putting something up for sale in trade for a week, not having it sell, then lowering the price, then not having it sell for another week, then lowering the price again...two months later you finally find the price point and sell it. Auction can accomplish this over a few days.
Also note that auctions tend to be slow and lazy until the day of the sale. Most people don't want to commit a million gold to sit on a bid for a week, so don't get too excited when you see a +3 for 300k. It's worth a shot to put in your own bid but you'll want to check back on it in the final hours because it will probably get jacked up quite suddenly.
Also note the way the system works is pretty good:
Serge bids 50,000 for an item.
Namo bids 1,000,000 for the same item.
The auction price is now 50,001.
Serge sees this and bids 60,000.
He is instantly outbid and the auction price goes to 60,001 -- Namo's bid is still active and winning.
Serge bids 1,200,000.
The auction price is now 1,000,001 and Namo gets his money back; Serge is now top bidder.
So you should really plug in the highest price you are willing to pay. It will only go as high as someone else's max bid. If you see the price is 50k and you are willing to pay 1.5 million, go ahead and plug in 1.5 million. You will automatically outbid (by 1 gold) anyone who offers less.
Of course, people can try to artificially jack up prices (and perhaps use a friend to do sort of a "reserve price") but they have no idea what the real max bid is and if they go over it, they could be stuck with buying the item (and any attempt to do a reserve could end up costing you 5% of the gold if the reserve isn't met).