So many people have asked about this sort of thing.
I am scratching my head as to why stuff like "navy" makes the list when this sort of thing hasn't.
It comes up again, and again, and again in various formats.
I hope it comes.
Seems more important than some other stuff that is on the radar.
I suspect the answer is because much of this doesn't fit the game.
Setting different formations would require an excessive amount of work, given that the AI would still have to calculate what to slot where, consider its destination and consider the map layout. Then after all that, it's still going to be left with the choice of pulling artillery in close, or having Medics/Capacitors in odd places. Square (Standard army shape) and Spearhead (What the shape becomes if it logically makes sense to, typically with Dreadnought) both occur naturally in the game, so those don't need to be added.
As for different stances, one of those doesn't make sense for how the game is (There's no stealth in the game, so Passive is worthless - and even once we get Stealth, unless the whole army has stealth, it won't make sense to use). One of those is already in the game (Defensive is how the units currently act). Which leaves Aggressive and Retreat. Which, sure, I wouldn't argue against, but they're far less of a concern than almost everything else on the list for many people. I can't design an entire Naval expansion to the game; I can just tell my units to pursue a fleeing army.