As I played through the backer build I would sometimes split my team into half to flank or such, but doing so makes it more difficult to keep track of what actions everyone is still capable of doing.
I would suggest that rather than having the quick-select icons in the bottom left corner be grey at all times they should instead change colour depending on the amount of AP a given unit has remaining, with the most obvious approach being swapping between blue, orange and grey depending on the actions availible, with perhaps an additional marker for when the trooper lacks AP for firing his currently equipped weapon, but still has the AP required to use one of his other items.