Disclaimer: I haven't playtested Dungeon World at all, much less with the Druid.
That said, three things struck me on reading it.
1) I like the focus on Shapeshifting as the core shtick of the Druid. They clearly needed something (and something different from 'nature-seeming spells', IMHO), and Shapeshifting is as fine a choice as any. The speak with animals and eventually natural stuff is good and feels like an extension of it. Yay.
2) Like one other previous poster, I'm not a big fan of the Human 'domesticated animal' thing. Seems trite, not terribly useful in many dungeons (certainly old-school ones), and kind of blah. I'd love to find something more flavorful for humans, but don't have a good suggestion to hand.
3) I don't like the 'Sustained by nature' bit coming as a mandatory move for the druid. Although I like it as an option to buy, it doesn't seem as intricately linked with the core shtick as the others.
OK, fourth thing: You need to add 'The Trackless Mire' or something similar as a possible terrain. Swamps and bogs are a staple of fantasy and Druids should be able to be at home in them. I would also call 'Arctic Circle' something more fantasy-sounding like, say, 'Frozen Wastes'.