Wow, that looks pretty awesome! If I had my mac, I'd try it immediately.
-Gan
P.S. Before I forget, thought of a few ideas:
-Marksman shoots in the direction of where the finger taps and if it hits, it hits. Means that the player will need to aim directly at the monster and it gives the chance to miss. Also add in a bit of randomness so that longer shots will be harder while when they get higher levels, shots are more on target.
-For beam spells, they take damage over time instead of all at once like projectiles.
Good ideas? Now if only we could get more for the warrior.