I'm surprised no one is proposing a Druid Mage who is trained in all 4 elements (earth, fire, water, air), and NOT trained at all in Nature.
I know, I know, I know... a Druid who isn't trained in Nature? Are you daft?
But think about it for a sec. We already have the Beastmaster who's our Nature-Boy... (that was actually going to be his official name, until they settled on Beastmaster)... And we could certainly see a whole pack of new elemental creatures fighting on the side of the Druid in the new expansion. So yes, we'll finally get some decent water spells/creatures, as well as filling out the other 3 elements.
Of course, this could also sound like a possible future Elementalist, but I wouldn't be surprised if the Druid is our first Elemental-Based Mage.... with a Mage innate ability that ties it all together in a Druid-ish sort of way. (having a flash back to SpaceBalls... "Funny, she doesn't look Druish..."