Not wanting to spam the Contest thread with just our conversation, I shall VM.
Hehe, my mistake, I was thinking about some Halo shit whilst writing...
Do you want to know how many possible roles there are?
Sure, they all link to one of the three archetypes; Warrior(mostly Strength and Agility), Ranger(agility), Mage(intelligence), but, what similarities are inbetween a Paladin and a Crypt Lord, aside from the attribute? With this, you can create like 6 heroes per race, with each with different AND clearly defined roles.
For the caster, I think you should emphasise it on your race's strategy. For instance, my casters are both buffers because my race is a 'counter-defense' race (not aggressive, like Orcs). So, if you're race is more offensive, I think the caster should be an offensive one. If you lack defensive factors, make his spells offensive-support, eg. like the Shaman's Bloodlust.