I think the book would have jumped a whole point in my estimation if they'd just given the elementalist appropriate 'bending' powers, a la Avatar: The Last Airbender. Make them cantrips or something, but let earth sorcerers extrude rocks from the ground, water sorcerers create shields of water, and so on. Flavor is important, and while a lot of the recent "Heroes of" books had great flavor, the class options in this one weren't as tasty.