According to an interview with a Blizzard developer posted elsewhere on this site:
"The BMAH has been successful at giving players that are focused on earning gold items to purchase, such as mounts, pets, transmog sets, and other things. It was also useful in phasing in access to the Brawler's Guild."
This statement came as a surprise to me, as previously I had regarded the BMAH as a big disappointment. When the Black Market Auction House first started last year, it included items you could actually use for PVE or PVP, such as current content heroic gear. But now, day after day goes by with ilvl 88 belts and brawler's guild invitations being the only items available. I get it that someone out there who plays with fashions on WoW wanted an ilvl 88 belt. But it is disappointing to see items like that listed day in and day out, instead of current gear. According to the Undermine Journal, which tracks bids on the BMAH, by server and by faction, those ilvl 88 items are very frequently getting only 0 or 1 bid per day, which is a way of saying that no one wants them. Yet, when an ilvl 535 item goes up, a dozen or more bids are recorded and the items sells for large amounts of gold, thus achieving what I thought was the intended goal of the BMAH as a gold sink to remove currency from the hands of hoarders and AH bots.
Please, Blizzard, bring back currently usable items to the BMAH for this next tier. Everyone who wants a belt from 2006 or a horsie from 2008 already has one by now. If they didn't, there would be many more bids for those items than there are. It's time to serve the hundreds of thousands of subscribers who play the game to progress on PVE and PVP content, not to hold little fashion shows.