Which game is this for? Do you have a demo? I like the general idea. I'm assuming that the player will be able to control a character of each race? Do you choose your party at the beginning of the game (like Final Fantasy I) or do you meet characters as you go along? All these things effect how the system will play out, so any information you can give on that end would be helpful for us to give feedback.
It's for Tower of the Spirit World. There is a demo, but it's dated, not really polished, and the work of 2-3 years with little feedback or playtesting from others.
At the start of the game, you create a party of four characters. They can be any combination of the races, so it's really up to what they player wants. As for the mutants, their element determines a lot about what skills they can learn, especially later. Water, for example, has healing spells and water-based spells, but will eventually learn ice-based spells. Fire has more AoE spells, and spells that can cause damage over time. Lightning has spells that are generally single target, but with higher damage.
I've also been working on new skills for the human classes, specifically the Scout. Currently, they have a standard skill called "Snare" that prevents a target from attacking(and ensures all attacks will hit them) for a single turn. It has a high hit rate on any non-flying enemy, including many of the smaller(human-sized) bosses. Larger bosses are simply too big for such a small trap to effect them. That's just one of the ideas, though. I have a few I'm throwing around, but the overall goal is to make every skill useful throughout the game.