470X just seems like way too much and for being a level 4 spell seems extremely easy to counter
While I do have to agree with this, you guys are discounting the light and dark effects of this spell. If a Light magician has cast the spell units get 15+X healing (per second), that is enough to reduce damage from any potential water spell, to almost half. So now we are looking at something like 200X more damage from an ordinary water spell.
And with the dark effect - player will want to cast this on his weakest units, lets say Goblin Warriors, who have (I believe 7 base attack values.) With the use of the Inner fire, their attack becomes 17+x. (this could bring the value to 30 for experienced spellcaster). This is a lethal force, and we need to make sure there is actually a counter for it.
But with that said - all the values you have seen in these spells are temporary and will change dramatically once we get down to balancing things in-game.