Yep, I'm planning to add charm as one of the points of the CC section, its indeed quite crazy.

In terms of oath/rage/bully and similar that does to the damage category and I think the main problem in the game here is uncontrolled damage stacking, although individual buffs could take a nerf as well. Making some bonuses additive instead of multiplicative as well as mutually exclusive might help.

Quartering the resistances could work with the current system, but I like the idea of not having absolute percentage based absorption more. Alternatively maybe cap them at smth like 75 + reduce the values.

GC actually contributes to damage, cc, and arguably survivability (since you can buff/heal/reduce enemy damage more) so yeah, it's a no-brainer atm.