Yeah, when the upgrade is finished, they retreat to the callin point, vanish and the new unit appears, now we've got it.
Hmmm, interesting workaround. The squad would lose all their previous vet, kill data etc. but would become the new unit. It would look a little inexplicable though if they just changed in the middle of the battlefield. They'd have to run to the call-in point to make it look alright.
The armour skirts isn't that implausible compared to this. The squad would spawn no matter how many casualties were taken and a full squad would spawn in it's place. The squad would be completely different in terms of weapons, looks, name, positioning etc. It would also be OP to suddenly go pop! and change to a more powerful squad in the middle of combat and replenish your losses.
It would also be OP to suddenly go pop! and change to a more powerful squad in the middle of combat and replenish your losses.
Some upgrades require a certain amount of the squad to be alive before you can upgrade them (riflenades etc.). I'm not entirely sure how this works. Still, I'd rather them retreat to the callin point because it just looks better and is more balanced.