Because of the daily quest limit being raised to 25 and a whole new set of extremely easy quests to run through on the Isle (doubly so on PvE servers), there has been an economic boom in the game. I can really only speak for my own server but I bet the trend has been similar through out all realms.
Influx of money on my server has meant inflation. Everything after Patch 2.4.0 has doubled and tripled within months. Ease of money has made people lazy about farming goods and more inclined to farm gold instead. This has created a supply shortage on basic goods like nethercloth, netherweb silk, primals, thick clefthoof leather, heavy knothide, cobra scales, etc.
For example:
(20) Thick Clefthoof Leather (Pre 2.4=50g, Post 2.4=120g)
(250) Mark of Sargeras (Pre 2.4=150g, Post 2.4=530g)
(1) Primal Life (Pre 2.4=10g, Post 2.4=28g)
(1) Cobra Scale (Pre 2.4=12g, Post 2.4=32g)
And even things that you would think would drop in prices like Void Crystals or Nether Vortexes all doubled as well.
There just hasn't been that much money you have to sink anymore into the game besides gems and enchants mats. People used to buy 1000s of golds worth of patterns but now you can get equivalent gear and weapons via badges.
That's why I think the Gigantique 22 slot bag is one of Blizzard's solutions to helping money dumps in our economy. A lot of people complain about AH fees but that's also one of the largest ways Blizzard dumps money from our economy....well that and Repair costs.
I also imagine for PvE servers, the inflation must be worse. On our server there is a huge detriment to doing daily quests and that's massive gankage. Since we're overrun by horde, it makes it a little less enticing to head out to the Isle on peak hours.
I would love to see the statistics on how many of those 2000g and 3000g rings are sold based on server...pvp, pve, rp. I must say that'd be an incredibly romantic gesture to give someone a 3000g ring. On our server though, you'd probably get ridiculed for it. Maybe it's time for ring graphics to appear on characters. I'd also love to see neck pieces as well. Wow, I digress. LOL. I guess economic talk doesn't hold interest that long. hehe.
I have no doubt that WoTL will have a 22 slot bag pattern available for tailors but what those mats might be and how expensive they might be at first, getting a few bags now and helping the economic dump isn't a bad short term solution. Besides, as my friend who bought nine of those bags said, he'd probably make up the money and then some in daily quests before the expansion.
FYI, get your first epic flying mount before you splurge on bags! It'll help you regain the gold faster!