User blog comment:ChickenRave/Elmye, the Reflection/@comment-7709681-20150206183208/@comment-26030737-20150208095144

This champion has 3 forms. People already say that champions who can switch to a whole new set of spells at will are unfair because it's like having 7 spells. Elmye could have 10 spells if their effects changed a lot for each form, imagine how unfair it would be. So my solution to get 3 forms was to make a minor yet important change in the spells' effect, making Barrier the only spell that actually has different effects (root/push/damage) and the others differing by the form of damage and their targeting method. This way, the spells don't change much so we can consider the three forms of Ethereal Sword and Psychic Chain as whole spells plus 2 halves for the variation they make, making both keys worth 2 spells basically. We end up with the equivalent of 8 different spells.

Passively forcing a transformation to keep using spells is the key to counter what you said in your first comment: you can't just pick one form, focus on AD or AP, and stay efficient all the time. You have to make a choice between dealing higher damage for one or two forms, and dealing lesser damage on all forms. You choose whether or not you can allow yourself some low-damage time for better damage after that. This champion can't spam spells during teamfights, because Form Shift's cooldown is what makes this champion balanced and changing his form to a less efficient one can be very problematic.