First off, no correlation can be made here between the idea of releasing a Remote Auction House feature and that of releasing epic equipment for sale. The ground is still quite firm on that slope.

Second, a player who has more time in a week to play the game than you has an advantage over you by this same standard. Someone that has an hour or more a day to use the Auction House than you do has an advantage, and they’re not even charged extra for it. The Remote Auction House provides no in-game functionality that isn’t already available to every single player as often as they can or want to use it. The only difference now is that, for an additional monthly fee, players can use the Auction House in a remote fashion without having to log into the game client.  (Source)

I’m not sure how many time Blizzard has to say they won’t sell gear before people will believe them.
It’s a legitimate concern. I’d share it if I weren’t confident about our commitment to our players and our ultimate goal of creating epic games with incredible support and bonus features. Some players fear this happening so much though, that they almost wait for it to happen. With nearly any announcement we make about additional features or flavor items which have a cost associated, this is then seen as a sign of the slippery slope, no matter how large the leap to an adequate assertion may be.

Our core philosophy has not changed and we feel we’re being very reasonable about the products and premium services we’re offering. They allow us to maintain a strong company, afford and maintain state-of-the-art tools and hardware, keep some of the most talented staff in the gaming industry around, and continue making great games.  (Source)