This type of system is more common in F2P titles really. It's how they survive as a F2P game.
Setting something like that in WoW would only really work if you weren't paying to play the game. Best thing they could do is just reduce what their services cost.
The dude doesn't understand that GW2 gems is an income that (sort of) compensates lack of subscription fee.
Mercarcher is hilarious though. One of the most profitable games at this moment is "stagnant" and the owners are selling shitty company called Blizzard. Damn, right. Sell this crap.
Also Vivendi is the majority share-holder, not the owner. They want to get out of the video game business and back more into Music and Telecom, where their roots are. Blizzard isn't going anywhere though, they're not going to be sold off for their IPs. When the merger happened they remained autonomous. It's not going to change.
As for your idea, the reason it works for GW2 is because GW2 is a F2P/P2W model. WoW is a P2P model. Things that work in one won't work in the other.
This idea was implemented not only in GW2 and Eve, but also currently by Sony (Krono).
It is not necessary for game to be f2p for having such feature. Only source of gems would be Blizzard store. But it would help with retaining players. For one player virtual gold means a lot (not necessarily in bad sense, farming/AHing takes time too) and 15$ are not much in comparison, for other player it might become hard to pay sub cost if he doesn't happen to like game as much as before, but he'd keep playing (for chat or just to see changes in game) if could buy sub time this way.
I have no clue what drawbacks people see.
-the people with most money to spend get character transfers, others reroll or quit
-many servers are dead
-Blizzard gets some money
-the people with most money spend them to buy gems, transfer with gems, and also put gems for sale so other people can buy them and they get gold. To get more gold, said people buy more gems, it's a sort of gold buying from Blizzard.
-dead servers fully die, but players from them move to other servers using gems bought with gold, so they're happy.
-Blizzard gets more money, as more people buy the gems to get gold.
When in doubt, mumble...
The PLEX cards in EVE are a perfect example. If Blizzard did something like that, a million people could pay for their subscriptions with these things and blizz would not lose a single penny, because at the end of the day those million "PLEX" cards still had to be bought with real money.
This however would make it easier for gold sellers to make gold with stolen credit cards, which is probably Blizzard's main reason for not doing anything like this.
---------- Post added 2012-11-15 at 12:03 AM ----------
People would be able to buy their subscription, transfers and other stuff with gold. Of course they would lose a lot money from this.
I mean, I don't support it one way or the other, but at the end of the day, this "Premium Currency" has to come from somewhere.
They still get their 25$ if Joe sells me the gems to do a server transfer. If nothing else, they'll make money by making "gems" sold for 10$=100 gems, and a server transfer costs 250 gems, leaving 50 gems rotting.
The typical Microsoft Points tactic.
Is it that these major game publishers don't want a franchise which posts billions in profit every financial year? Or that they don't have the capital lying around to make such a massive investment?
I know Disney recently made a large purchase you may or may not be aware of. Let's try and keep in mind that can't afford ≠ don't want.