What exactly do envision for dwarf mode? Most players are against a 'wizard' or 'mage' trained like any other military unit, and a good number don't want to see dwarfs screwing around with magic in the first place.
As far as the different flavors of magic go, I assume that the "spheres" already in place (that define civ artwork, likes/dislikes, and deities) would influence and generate the magic for a particular world. I don't think all magic users should derive their abilities from religion, however. Perhaps, like many polytheistic mythos, the creation event of a world be should directly controlled by the universe's deities, and then, in a sense, 'left alone,' so the associated magical influences are permitted to grow, evolve, spread, and coalesce on their own. I really don't want an Aristotelian-atomic theory of magic - its so overdone and naive, with clear-cut antagonistic relationships and predictable uses. I know you have tried to expand that by introducing life, death, and blood, which helps, but it also makes a modder's job (and initially the coder's job) difficult because they have to consider how each type of magic interacts with the world and each other.
Assuming the "wizard tower" mode comes to fruition, either as a separate mode or a consequence of adventure/fortress modes, I want experimentation to be one of the main focuses. If I have some herbs associated with nature and rain, and a flower named after the goddess of snails, and I cast a spell of courage over the resulting potion, what happens when I feed it to a puppy? The game should be able to handle that without rolling its psuedodice, and there should be an intuition that evolves after playing within the world's magic.