I like the game if it is a typical wargame, to have enough modifiers and a low range on the roll, that if you stack the modifiers you can be almost certain of the outcome.
An example would be giving elite troops an order to take cover in heavy terrain when under incoming fire, I would expect them to do it.
I would expect heavy troops at long range in cover to be very hard to get rid of.
I would expect elite troops in power armour engaging light raw recruits to win.
I would not like to see raw light troops vs a mega death tank win because even though the tank gets +4 you are rolling a d20.
I want to know that a sensible bit of tactical planning is not likely to be undone by crappy dice rolls, possible yes, but likely no.