[Samhain]

Mages are definitely vulnerable. That's why Arrow Fend is so nice. If you don't have that, you can give your most valued mages 0 encumbrance shields for protection. Or, use some shield equipped chaff up front set to guard commander for a commander set back behind your mages. As long as the back commander is still in range, the AI archers will keep firing at the chaff even after they move back out of the way.

For Earth mages, I always like to cast Summon Earth power for both the reinvigoration as well as the reduced fatigue for Earth spells it gives me. Then I'll throw on Ironskin, Stoneskin, or Invulnerability depending on what I have access to and what is being thrown back at me. These Earth buffs are usually enough to protect from arrows and sling stones.

For the range/fatigue issue, it is good to script buffs at the beginning. And, position your mages so that the enemy is in range when they are done.

In my experience, you generally don't have to worry about scripting the attack spells as the AI will tend to use the spell most likely to kill the most troops anyway. It mostly has trouble getting the buffs and battlefield enchantments right. So, don't fret filling your queue with all buffs or even a couple of holds (which allow the mages to recoup fatigue) to provide time for the enemy to close.

One thing AI is infamous for though is pushing out battlefield summons when no good Evocation targets are in range. Death mages who should be holding back for Shadow Blast or Banefire in particular love to fatigue themselves first with Raise Skeletons for instance. For this reason, I'll sometimes delay researching Enchantment when playing a Death nation just to keep my mages from casting it unless I want to get that spell out early for an opponent particularly vulnerable to such a strategy.

And, yes, having your troops guard commander is also intended to reduce collateral damage. But, that's going to happen unless you are playing a nation like Abyssia and have troops immune to nearly all of your Evoc spells.