User blog comment:The Milkman/Multiplayer Ideas/@comment-123.2.70.12-20120501121458/@comment-4237253-20120501234056

I guess that depends on the threat they pose to the player. If they were as enduring and powerful as 2 brutes at once, you would only need 1.

On the converse, they could make them weaker for the sake of balance to allow multiple Praetorians on the field.