We pay a monthly subscription fee. We pay for each new XPAC. Making more money for the shareholders is good. Squeezing your customers...not so good. Successful companies don't alienate their long-term loyal customers. In this case, they're taking our money, using it to develop additional content...and selling it back to us for additional monies. Instead of making it available in-game by earning it.
Everything they're selling, is one less in-game reward, one less quest chain, one less mini-boss...and that much more mindless grinding and unimaginative, "phoned in" game design instead of something cool to do, with a cool reward for accomplishing it in-game. Whether you buy anything from the store or not, that impacts each of us.
Blizz turned $1+ Billion USD in profit for FY2012. That's on roughly $4.5 Billion in revenue. That's a phenomenal profit ratio. Just how happy do we want to make the shareholders at our expense? You might note, that successful companies make their customers happy. Generally (and loosely) speaking, if the customers are happy, the shareholders are going to be happy. You might also note, that shareholders are an insatiable breed. Ditto for corporate bean-counters. With Vivendi putting the screws to Blizz, no amount of conceivable profit is ever going to be enough to fill their gaping (and bottomless) maw. They're going to want more, more, more...