I played through one of the SD Normandy campaigns last and had an idea I'd like to share.
First I'll describe the mechanic. When you select a card this units become available. If one of those units die then the card stack is reduced. It therefore becomes less desirable and is supposed to make one care about losing units.
Now my idea is to increase veterancy on cards that are used and survive a battle. Pretty simple. Unit preservation is incentivized as is 1/2 stacks. Less units available in a stack, do to losses, yet may be worth it for veterancy.
This of course assumes S D 2 has a similar campaign card system which it very well may not.