Yeah, here at the WoW.com high-rise, we were all a little surprised by the announcement of the Pet Store and its microtransactionalized non-combat pets -- but seriously, it's not that big a deal, people. Hitch your bandwagons to that slippery slope fallacy all you want, but pets offer no plausible in-game advantage. The whole experience is roughly equivalent to buying a TCG pet off of eBay, just slightly more convenient and reasonably easier to live with.
Anyway, of course the forums are mad about it, or at least the incredibly vocal minority on the forums is. And they've made post after post about how the Pet Store has completely ruined WoW. Well, official forums MVP Palehoof has a rebuttal, and it's the largest green wall this side of Fenway Park.
If you want a rundown of just how many times WoW has been "ruined" by an addition, deletion, or alteration to the game, you can read Palehoof's post on the official forums.