I notice that when I use auto-resolve, my sov uses a lot of magic, where much more damage can be done with melee weapons, and the sov is better equipped to take melee hits, instead of the others in the army.
So one suggestion is: can we have an autoresolve option to disable magic use?
In addition, the AI opponents will also use magic too much magic, so maybe you need to tweak the balance here, to make the AI consider whether or not to use magic.