I have tried all three and they are not as effective as players think the benefit % per cost ratio is not balance spending 495 varium or 7000 credits for less than 10% is not giving the player what they pay for.
Those three cores should be stackable. They need to have a higher percentage, especially for the classes without hybrid Armors and shadow arts.
They need to have a better way at calculating the cost to the effective percent ratio instead of making all core skills cost the same.
If they are high damage than they should be the most expensive.
especially for the classes without hybrid Armors and shadow arts.
That's why classes without these have different skills to make up for it. They have SA? You have DA. They have passive Armor? You have BloodLust. DA goes through passive Armor easily; take away boosted damage (DA) from the Armor, only Mages can do it.