[Micah]

Nature has horrible evocation spells, and astral isn't very good against large hordes of troops, but mind burn spam is fairly nice if your opponent is fielding lots of expensive units, like cavalry, and soul slay for anything larger than that. Both of those paths are more focused on support magic. Astral is the king of winning fights off the battlefield, with great mobility spells (teleport/gateway/astral travel) and mind hunt which can take out enemy leaders, leaving their troops stranded. Nature has great global enchantments.

Astral especially has some really nice high level spells. Try casting astral tempest, antimagic and will of the fates in a large battle (against human-type opponents, astral tempest won't be so good against high hp or MR opposition since your own troops are fragile) and see how things go.

Also, drop body ethereal, luck, and regeneration on an SC chassis and watch them go to town, just make sure they have some reinvigoration and decent protection and they should be good to go.