My boyfriend played WOW from first year pre-dlc. He's been making the same prediction. Micro transactions will start with cosmetic only, then they will start selling items that boost xp, gear, etc. The purchases won't be mandatory- you can choose to grind for it instead but it'll be a long, slow grind. It's what ruined WOW for him. In the end you'll start to feel like you have to make these purchases to keep up- 8 hours of grinding vs a couple of dollars and it's done. Some of us won't be surprised when we start seeing items sold by Tess that have nothing to do with ridiculous dance moves and gestures.