To begin with, i love the skill modifiers mechanic overall. But i think there is some disbalance regarding damage modifiers.
Lets take a look at Thunderstrike:
Swift Judgement(1 point cost) - reduces willpower cost by -19. Given that base cost is 100, this modifier adds ~20% effectiveness. It is cool.
Another modifier - Smiting Hunger(2 point cost) - add 20% to average damage, but in fact avarage damage changed from 97 to 103 because there are a lot other damage modifiers from loot etc. Though it costs twice as much points, its effectiveness is 5% and it will be even less as character progresses.
That is pretty much the same for skills based on weapon damage.
To be competitive, or at least viable - damage modifiers could be multiplicative with other damage sources or just scaled up.
Thanks for reading.
Love Wolcen)