Originally Posted by Gelatini Jejunator
There's a pretty major difference between the two; Fire Spinners are extremely adept at handling heat and using fire effectively, Ace Trainers merely have lots of knowledge and skills in the type they are using.
I assume the reason there cannot be more than one of each class is to keep things interesting; you don't want to have the /exact/ same job description and Pokemon as another person, do you?
THIS. That, and in the Fire Spinner's case, they come from really harsh enviroments, so they're expected to really have good talents. The Water Specialist would have extreme skill in swimming, the Aerial Artist is really fast (as is her Pokes), the Earth Trainer is VERY physically strong and has Pokemon to match. Ace Trainers probably have Pokedexes-which rock because your character shouldn't know too much about Pokemon from other regions if you're not from that region, and if you are, Kanto Pokemon would be very foregin. The Mages have Psychic Skills JUST TO KEEP UP with them.
Besides, Gold, you can always ask MGS for his Light Mage roll, or 5TDS for her Dark Mage roll. I have doubts they'll give their positions up, but I guess they would consider it at least.