Defile/Desecrate Enchantments

Hero AI for these two skills can be rather perplexing. After testing it in FoW and a couple other places, here's my observations on how the AI works:
* Heroes don't spam these skills on recharge. I'm assuming some requirement must be met before the hero uses the skill.
* Heroes will use the skill on any enchanted foes.
* Heroes will use the skill on any foes with ranged attacks. This includes casters and may extend to Rangers and Paragons.
* The Shadow Beasts attack at melee range with Necromancer profession. I notice the heroes aren't likely to use Defile/Desecrate until they use a spell, but I can't guarantee so. Otherwise they don't use the skill if the Shadow Beasts are only autoattacking.

So I'd like to confirm if anyone else sees this behavior with the skills. A couple other things I haven't checked is:
* Melee professions that use spells i.e. Thorn Wolves. Dervish enemies would be hard to confirm this since they use mostly enchantments for spells.
* If they use on Rangers and Paragons. I'm not sure if heroes cast on enemies because they use ranged attacks or are of caster profession. The Shadow Beasts at Tower in FoW and casters in Spider Cave may have thwarted my observations of such.

AFAIK AI (almost) never makes a ranged/melee or caster/physical profession distinction. If something is holding a caster weapon, its assumed to be a caster no matter the profession, and if it has a physical weapon then its assumed to be a physical profession.

The only time the AI follows other rules are for spells with very specific conditions like Strength of Honor.

I'll play around a bit and see if I can figure out what makes em tick.

EDIT:

As far as I can tell the AI considers DE a valid skill to use in the following situations:

1. On enemies with enchantments. Good choice.

OR

2. On enemies with low health. We're talking <10% here. This is very, very dumb. As a 2s cast skill its liable to take longer to cast than the enemy has time to live.

The 2nd condition should be gotten rid of. Ideally, as an AoE nuke, the AI should prioritize large mobs/enchanted targets/any target in that order.

Tested on the Jade Brotherhood right outside the marketplace. RE is never cast on non-enchanted foes even when its the only skill on the bar until the enemy is near death, at which point all 3 necromancer heroes decide RE is finally better than wanding. Same goes for both the casters and the physicals.