Heroes VII

Let's put it this way, in Total War, this approach worked in many cases, although there were exceptions. But was it the same in the fourth installment of Heroes? Regardless, implementing the idea in the right direction shouldn't be overly complicated: just balance the hero's guard properly. Plus, balance the negative effects that the fallen hero's army will receive (or eliminate them altogether, and let them fight as they always have). Plus, the enemy also has a brain and should at least minimally prevent you from using this tactic and take advantage of any opportunities that arise. That's the gist of it.