If I may comment on the OP's organization (only to help some great ideas get off the ground), as someone who constantly receives spell suggestions for his own
completely unrelated Minecraft mod...
It's not intuitive to do this, but I think you should abandon the list-iness of your ideas, narrow them down, and go into a little more depth with how your ideas will be interesting. The juiciest part is the very last "Some things I envision with this system:", because it's brief and gives some really cool
consequences of your suggestions, rather than just running through them. The idea of raising your fallen king is genuinely amazing, and the idea of ensuring each of your dwarves has a magic sword is also fun (anyone who plays DF surely enjoys having their ducks in a row.) Consequences are good, little details are bad

As you focus more on the mechanics, you may realize some of your ideas don't have a great justification (not to imply that they don't), and I'd encourage you to remove any that you can't justify.
Example things I'd like to know: why would splitting spells into Arcane and Divine be interesting? Is it worth the added complexity of having two spell trees (especially when both trees have a lot of summon abilities?) Speaking of, why the focus on summoning creatures? Why is that appealing? Etc.
I receive spell suggestions constantly, and it'd be a million times easier to find interesting ideas if they'd do this. I don't care if a spell is "Fire" or "Ice" or has an explicitly defined progression, but I care if the mechanic itself is interesting. The absolute worst is when someone has "Generic Bolt I: does 3 damage, Generic Bolt II: does 5 damage, ...", hehe. Consequently, I've thought about making Generic Bolt a real spell

@Novel:
A great way to give magic some uniqueness and depth would be to randomly generate anything possible-- make summoning spells summon a specific creature with a random name and type (Dak'thul the Demon-Sponge!), give projectile spells a random appearance and element (Summons a great cloud of mist as the dwarf squints his eyes and shudders violently!), etc. That would be a lot of fun