I assumed it would only be players buying them as well, and it would be interesting to know how many Blizzard actually buy. There's a huge difference in the price of tokens in different regions, and I wonder if that's partially due to manipulation by Blizzard to make tokens less valuable in regiouns like North America where people will pay more money for less gold.
But I think you're misjudging negative reaction people have to "pay to win." Maybe I'm not correctly reading the average player, but I don't think it's so much a matter of Blizzard having to keep up the appearance of fairness. The underground gold market has been around for so long and in so many games that people expect that money can buy in-game currency. There are other games which are designed to be fair like first-person shooters, but part of the draw of MMOs is that they are explicitly not fair. Coming in as a new player, you have to compete against people with significant gear advantages, and there's an aspect of this that's actually ego-boosting. If you can compete with people who have more resources, not necessarily win but at least operate close to their level, you can feel good about your skill, and when someone else has an advantage, you can excuse it because you know the system isn't fair. It's the same with games of chance, where you know that some of your failings are attributed to bad luck and not your own failings.
Where "pay to win" goes bad is when you feel like you need to fork over excessive amounts of money to compete at all and feel like the game is just trying to squeeze you for money. But the way WoW is designed, it's relatively easy to get to the gear level of other players, and what's really valuable is having people who you can work closely with. In the time it takes to develop those relationships, you will have more than enough put into the game to have the resources you need to compete. Although gold can be a nice boost and snag a few top-notch pieces of gear, it's mostly unnecessary, and the really expensive items are usually vanity items.
So the unfairness is actually only a small part of the game which serves to excuse personal failings, and the really valuable resources: friends, time, and skill, are things which can't be bought.
But I think you're misjudging negative reaction people have to "pay to win." Maybe I'm not correctly reading the average player, but I don't think it's so much a matter of Blizzard having to keep up the appearance of fairness. The underground gold market has been around for so long and in so many games that people expect that money can buy in-game currency. There are other games which are designed to be fair like first-person shooters, but part of the draw of MMOs is that they are explicitly not fair. Coming in as a new player, you have to compete against people with significant gear advantages, and there's an aspect of this that's actually ego-boosting. If you can compete with people who have more resources, not necessarily win but at least operate close to their level, you can feel good about your skill, and when someone else has an advantage, you can excuse it because you know the system isn't fair. It's the same with games of chance, where you know that some of your failings are attributed to bad luck and not your own failings.
Where "pay to win" goes bad is when you feel like you need to fork over excessive amounts of money to compete at all and feel like the game is just trying to squeeze you for money. But the way WoW is designed, it's relatively easy to get to the gear level of other players, and what's really valuable is having people who you can work closely with. In the time it takes to develop those relationships, you will have more than enough put into the game to have the resources you need to compete. Although gold can be a nice boost and snag a few top-notch pieces of gear, it's mostly unnecessary, and the really expensive items are usually vanity items.
So the unfairness is actually only a small part of the game which serves to excuse personal failings, and the really valuable resources: friends, time, and skill, are things which can't be bought.