It was only a matter of time before they introduced item shops. I wouldn't be surprised if they started selling stuff other than just pets soon too.

WoW is losing subscribers, so Blizzard is trying to get as much money as possible from the people who still play it. Just look at the recent features: paid faction change, paid race change, and now paid vanity pets.

They haven't opened a new realm (in the EU) for almost a year now... They used to open 1-2 new ones every 3 or so months before.