Some more thoughts on army bLasting spell.
In terms of game-play, "Vengeance of the Dead" seems to be a good way to counter army bLasting - if we can make them good even for undeads.
If we still found army bLasting still too annoying, we can introduce a few new spells in other magic paths to make mass murderers more vulnerable. Some examples:
"Curse of the Deads", a spell to curse a commander with a large body-count remotely.
"Mark of Kurgi", a spell to horror-mark a mass murderer from a distance - for later Horror attack.
"Smite of Justice", a thunderbolt to strike whoever kill too many.
"Scythe of Conscience", renders whoever kill too many feeblemind
?
Just some random thoughts.