MArcomage

During a match it's easy to have many cards from enemy deck(I mean: militia, basic wall, lookout towers, reinforced gate... are almost in all decks).
another option is to discard cards not from your deck to make a combo with wind and messanger.

Reduced stock & wall gain by one, increased cost by 1B & 1G

Your idea is fun too, but a completely different one.
I'd say: create 'em ;-)