I agree with almost all of Ahrimans points, Mithril weapons could use it's cost cut in half, and the stack damage spells really need a limit to how many units it can damage at once or tighter damage limits, you use just afew ritualists on a stack that would have 99.9% odds killing you, and suddenly its down to 8.2% odds, and tsunami is way to much for every cultist to use, and even destroying improvements along the coast.
A limit of 3-6 units damaged per caster, 15-30% cap or made less spammable would be good, catapults are balanced because you need to risk losing them if you want to -try- and do collateral damage and possibly lose the catapult and then need to wait for the catapult to heal up before attempting again, but with a spell you can just hit the button and use it nonestop.
One way to reduce the power of it is a % chance for the caster to become fatiqued after using the spell often, and while fatiqued it can't cast the spell until it wears off, good way to balance the insanely powerful spells like ring of flame and tsunami.
Tsunami might be balanced if it kept the improvement destroying, and had a damage bonus against units on water, but low damage on land.
A limit of 3-6 units damaged per caster, 15-30% cap or made less spammable would be good, catapults are balanced because you need to risk losing them if you want to -try- and do collateral damage and possibly lose the catapult and then need to wait for the catapult to heal up before attempting again, but with a spell you can just hit the button and use it nonestop.
One way to reduce the power of it is a % chance for the caster to become fatiqued after using the spell often, and while fatiqued it can't cast the spell until it wears off, good way to balance the insanely powerful spells like ring of flame and tsunami.
Tsunami might be balanced if it kept the improvement destroying, and had a damage bonus against units on water, but low damage on land.