You can't plan around having a random kin join your team though.
My idea: Choosing rage during level up gives you two versions of the power (similar to adaptation on bio). One will be the current rage on test, with the overlap possibility and crash. The second will be non stacking and just refresh on reuse, similar to hasten. Make them mutually exclusive like the adaptation toggles and then you can choose to either deal with the crash for the overlapping buffs, or not have to deal with it at all with a constant power level (even if its lower).
