I've been leveling my pets off the critters surrounding Halfhill and the farmland just to the west of Halfhill. With a beast with Devour, it's been pretty smooth sailing because they're almost always all critters, or sometimes one or two aquatics mixed in there, which go down easy.
Another place is around the old BMAH area up on the Veiled Stair, which also has 100% critters.
All of these areas are super crowded this weekend, though.
I'm looking for some good pet battle areas in Draenor so I can do some double-duty of leveling pets and getting the achievements/statue. Any ideas?