Yeah but then that will create two problems which were also present in at least 9.0 Torghast.

1. Imbalance among Jobs regarding the powers they get. I remember Shaman getting some insanely cool things like a permanent Bloodlust. Meanwhile Priest was... Awful. Boring besides the one power that let you stack damage taken into a buff, releasing all of that into a DoT cast. Of course that was also limited in a way by your health (maxed out at X10 your health? But you could get health increase powers to beef that up).

2. Further on that, levels and bosses being balanced around getting the most optimal powers. I remember being quite upset at some nerfs both my favourite specs' powers got (Discipline Priest and Arcane Mage).

It sounds fun on paper but it really depends on the powers in practice IMO.