Hi.
Because steam cloud is not 100% reliable and I've had to deal with this problem of reunlocking everything with other games like this, coupled with the fact game balance is largely tied to what cards are available, there should be an option to unlock all cards, decks, modes, etc. available in the options.
I personally do not find it fun to be forced to play to unlock stuff. Doubly so if content is added later or a save is lost. I simply just want the option to unlock everything. Then those that enjoy unlocks and less at once can enjoy that, and those that just want to get to the hard part/not be limited in strategy can also do that.