[SlipperyJim]

I'm sorry to say this, but you're going to have to learn how to script your commanders -- especially your mages. Simply telling them to "Cast Spells" will be okay as long as you have an overwhelming advantage, but it's no way to win a close contest of any kind. More importantly, you are actually depriving yourself of a lot of the fun of the game by leaving spellcasting in the AI's hands. Magic is a huge part of Dom3. Roll up your sleeves and take charge!

Fortunately, as Endoperez noted, the game allows you to save a number of scripts with hotkeys. So let's say that you're playing MA Ulm. Set a script for a Master Smith to Summon Earthpower, Blade Wind x 4. Make that script #1. Now you can tell every Master Smith to follow that script by highlighting them and pressing the '1' key. Cool! There's some micromanagement, but it's not too bad.