A mouse baed fighting style. I believe only Black & White (mostly the first one, which was the better one) accomplished that. Basically the player would click on different parts of the body of the enemy creature and your creature would attack depending on the areas you clickied or how many times you clicked and all. Using mouse gestures you could make creatures use spells, click & hold on the creature to make him block.. etc. etc.

So yeah, it's possible and is WAY more fun when done like this over keyboard. But then again, it takes a lot more work and skill so it's in the end upto you.