Currently there are 6 schools of magic, 4 for the elements, one for combat / warrior skills and the other for ranger / survivor skills.
The elemental spells allow Larian to show off how spells can interact with each other and the world, etc (and they may be the most developed), but you will be able to pretty much build your characters as you wish (as source magic is a big part of the plot, I don't imagine you can completely ignore it).
There will be a kickstarter update about skills at some point, as well as combat.