This is a hard no. I like the idea of burning cards for cards but not RW packs. This is like trading pennies for quarters. It's a huge fu to those who bought.
Alternative:
I think that a card burn mechanic should be applied to unlocking SB reward cards.
who cares who bought at this point? everything is down, everyone is in the red, no one's cards are worth jack shit, and no one is buying RW packs.