Great stuff! One thing I think would be interesting to make this a true challenge--some kind of modifier that forces you to change subclasses between rounds or sets of rounds. For example, a modifier that increases damage to void/solar subclasses and/or reduces damage caused by void/solar subclasses...then have it switch up so that you have to complete a certain number of rounds with each of your subclasses in order to progress. It would be like the old elemental burns but instead it would be focused on you and your subclass choice. Would pair nicely with the Entropy modifier and different burn modifiers so that you really have to be as resourceful as possible with all your subclasses to do well. Plus it would force everyone to try out every subclass on their character to be successful.