After reading each and every post on this thread, it seems Atma has made the most sense out of all of this. I am totally against the OP's original concept and agree that he/she is just pushing for something they think would be "so cool!" Even after the concept changed from "everyone turns into beasts!" (ugh) to "only beastmasters turn into beasts!" I just couldn't envision anything like it. In my opinion it's full of cheese and needs to stay in games like PSU or Pokemon.

What I can envision is something more along the lines of the ability to have a Summoner trade places with their summon thereby letting the player control/become the summoned avatar. I'm all for pet classes and all, but this OP seems to be fueled by self-righteous ambitions for a poorly thought-out pubescant concept.