When I was in my inventory I noticed in the top left were you make upgrades to your class, there were three available slots (one for the current class being used and the other for the unavailable subclass). Does this mean there could be a third subclass? Post your opinion.
Most likely yes. They are hinting that. I don't think they would put a blank box for no reason lol. In the end each class will be able to use all three types..solar, void, and ark.