[Pocus]

a 'potency' (threat in this case) parameter have not to just take into account what is the current status of the unit (routing, or being a badass Niefel berseked), it can also use a memory of what the unit did, by counting the gold/gem value of units killed by this threat. For example, as soon as the Niefel start to kill Seraphs, his threat value would go through the roof, and he would be targetted again by the seraphs?
just my two eurocents.