Both of these are iconic and differentiate GD from other RPG’s. Aether damage with its green fires are eerily otherworldly. Chaos damage again has that cool factor that no other damage type has for me. Pink fires in WH40k games are a big deal for me.
Perhaps these could be locked behind player choices. I understand that character development is not really a thing in this type of ARPG, but gradually becoming corrupted and insane is one of my favorite themes in video games. Speaking of which, there could also be (mastery-specific?) quest-chains for things like shamans descending into cannibalism (or not, and siding with Ultos or something).
The only thing I don’t like about that is having to level even more characters for trying out builds, but I guess that’s what gives a game replay-value.