What would you say about a pop-cap timer for US?
e.g. if you leave a vehicle, the vehicle still counts as pop-cap until:
a. 5 mins (while that time alliis can't take the vehicle)
b. enemy gets it.
c. it gets destroyed.
So US still can use the crew-funktion. But puishing your pop-cap limit or giving stuff too alliis will be very difficult.
I think you are over estimating the usefulness of the USF pop cap issue.
If your enemy is fielding tanks over their popcap chances are they will have no infantry/struggle to reinforce.
Its also a pig to micromanage a mass of fairly fragile armour, especially given the tendency of pathing to freak out when moving more than one tank in a straight line through an empty field.
I'd be happy for it to be replaced with a passive repair function instead (removing crews) as I've never found a use/had enough fuel to really exploit the pop cap issue.