What about interactive Tactical Combat ?

[Taqwus]

It's also true that there are behaviors that would be known to an actual commander, but are nowhere documented and thus can only be found by experimentation.

Behaviors such as a half-dozen mage-priests ALL completely neglecting to cast Bless when there are a few dozen sacred units in range, for instance, in favor of skellispamming; archers firing into a melee; troops cheerfully running through the left-behind cold/poison auras of their fellow monsters and dying because of it; mages casting Touch of Madness on their own side's archers and mages, thus stupidly ruining an otherwise perfectly valid deployment... and since the AI is perfectly incapable of avoiding much of what can go wrong, the only way to deal with this is to be aware of all this nonsense beforehand. That's the "unfair advantage" waiting to be discovered. Knowing one's own army is required for any commander.

ALL of that should, in fact, would be perfectly reasonable to know before battle. A simulator would NOT grant any additional information in pinpointing an opponent's disposition, tactics or use of resources. It WOULD grant information about what behavior they might have so people don't have to GUESS about such things as, say, "what happens if I mix units with different speeds in a squad with attack orders" or so forth.