IMO they should just make it so 25 random cards can be traded for an old card album, or 100 random cards for a mystic card album.
It would saturate the market for a couple of weeks then stabilize and offer some form of retribution for terribad cards.
Hm, we already have enough instance & MVPs to obtain OCAs and MCAs. I personally think it'd be better if the exchange for the cards can be diverted to somewhere else, something that won't affect the game balance and the cash shop (like costumes).
Edited by DeadIntern, 19 March 2017 - 07:55 PM.