...Why just because some Mystics can transform whe must assume all mystics can transform? Many people can contort, but not all people. Many people can ride a bike, but not all people. Many people can eat sugar without having health problems due to diabetes, but not all people can.
Just because some Mystics can transform, we can't assume all can. Either it is an ability that needs training, a common one they were unable to learn or something related to health, by what we have until now, unless we are told otherwise we can only assume that some can and some can't.
...Am I the only one that thinks the reason Flea looks like a girl is because he is a travestite? What, there can't be gay videogame characters?