Of all the many things that could be done to make the Auction House a less frustrating and intimidating experience for players, three stand out to me. First, Blizzard needs to fix the insane inflation in the economy. Second, it needs to fix what people see when they click on an auctioneer, and lastly, it needs to allow farmers to fill buy orders instead of posting stock for sale. These three changes, if made, would greatly equalize the economy and serve to reduce the drudgery that the vast majority of players have to deal with.
What the heck are buy orders?
I'll start with buy orders because it's the least obvious issue. Right now, when a farmer wants to make some gold for a BoE or a mount or whatever, they go and farm and then come back to a city and dump everything they've made onto the AH. Nobody likes waiting for their money, and most farmers have been burned by a huge batch of goods coming back, minus the auctioneers' listing cut, unsold due to too much competition. In order to have to wait to lose money for all the hard work they did, they'll list their goods more cheaply than they're perhaps worth.