This would be a racial or Personality idea.

What it does: Having Flex Cast available on your province allows you to select from a drop down the following 3 options "Empowered Casting" "Normal Casting" "Subdued Casting".

Depending on which option you have selected your offensive spells are effected as such:

Empowered Casting - +100% Spell Damage, +100% Rune Cost, +100% mana cost, +100% Honour Gained (Rounded Up)

Normal Casting - Normal Everything

Subdued Casting - -50% Spell Damage, -50% Rune Cost, -50% Mana Cost, -50% Honour Gained (Rounded Down)

As you can imagine there are different situations that would benefit both cases. Would make for an interesting dynamic.