So I've been thinking about how Balance doesn't have a prism, and I googled it just to see what people thought about the difficulty caused by this (I was considering making a Balance.) Most people responded with something along the lines of "Balance doesn't have an opposite school."
The dictionary definition of Balance is when all elements are equal or in their correct proportions. When everything is in their respective positions in the natural order of the Universe.
The opposite of Balance, therefore, would be chaos; when everything is OUT of order.
Here's where Myth comes into it. A myth or legend is a widespread false idea. In Wizard101, the entire point of the school of Myth is to summon myths to aid you. To bring into existence what cannot be; to disrupt the natural order of the Universe, therefore creating Chaos.
Also, Wysteria calls Myth Chaos as well. Heironimus Bunch describes it as: "the magic of the unexpected, the unusual, the unpredictable. It defies logic..."
There's literally no reason for storm and myth to be opposites.
While in real life they're not really opposite, they boost each other in the game for the sake of balance. You can't have 4 of the 6 main schools boost each other and have myth and storm off in their own world. I agree that we need a solution because balance doesn't boost anything and it needs a prism, it would just be unfair to boost myth.