We’re exploring the possibility of giving players a way to buy tradable game-time tokens for the purpose of exchanging them in-game with other players for gold. Our current thought on this is that it would give players a way to use their surplus gold to cover some of their subscription cost, while giving players who might have less play time an option for acquiring gold from other players through a legit and secure system. A few other online games offer a similar option, and players have suggested that they’d be interested in seeing something along those lines in WoW. We agree it could be a good fit for the game, and we look forward to any feedback you have as we continue to look into this feature.
To me this would be a great option for those of us with surplus virtual currency. I think it would be very interesting to see this flesh out if it were to come to fruition. It would definitely put a cap on illegitmate means of buying and selling gold, and put a pretty solid ratio on g/$ exchange rate, which to me would be fun to watch evolve over time, and I hope it's something that some of our already favorite AH tracking addons/websites would keep an eye on.
On the other hand, I'm not convinced that Blizzard will ever end up taking this avenue at all, as they've tried other avenues in converting gold to $ such as the guardian cub in WoW and RMAH in Diablo, and have since pulled both programs. That's not to say that there's absolutely no way this would happen, but I would hope they're approaching things like this with a little more care now, and if they do introduce it that it's well thought out. One can dream!
For further discussion on this topic, check out this thread on The Consortium Forums.