I understand need to increase human opfor to 2 players in case if mission is very large and has more than just one active front.
From my point of view. Human opfor
should primarily play from map view or external view
follow the original intent, plan and routing.
react to situation changes in mission.
For example if blue comes from unexpected direction.
react to minefields / obstacles made by player.
and in the end, making decition when to retreat. -> when opfor has 1/3 or more losses. Must retreat or surrender if 2/3
If possible, create room for illusion of humanistic error = Not to win the battle but to make immersion
And as most important of all... Aim to make mission for all the blue force players the most immersive and enjoyable as possible (in that order.)
In DOW mission OPFOR player purpose should to create immersive mission.
In TANKS mission Opfor player aim should be blue force enjoyment and fun.
In short... Aim should not be to Win, but to make mission better, by making it more immersive, surprising and fun.