Hi,
I'd like to be able to trade cards I don't want for wildcards of the same rarity. For example, since historic is ruined by alchemy treatment, I have no user for Elvish Archdruid, becasue it's banned in other formats. I have used wildcards to craft it and now it's a dead card. It would be very nice to be able to trade it for a card I actually want to play.

This way, the game stays attractive much longer thanks to being able to craft interesting decks and not being afraid of losing hard-ground wildcards for something I dislike in the end.

You know, something like paper magic trading...