i Think if we had a simple command which is similar to "GET IN" except this could be used on buildings instead of vehicles etc, could make things interesting.
when an order is placed for the squad in your command to Garrison the selected object lets say a building.... makes the AI get into the building and defend it using the positions available i.e. position 1,2,3
also now weapon stabilization is confirmed the AI could use their bipods or at least rest their weapons out side of windows.
"2,3,4,5,6 garrison the building 200m" something like that would suffice