You should make premium cards available offline in 1.7, at least in the multiplayer hotseat. I don't want to waste another player's time online when I am trying to tune a constructed deck, and I don't want to take losses on a deck I know is probably bad. It's hard to know if a deck is working correctly without playing it a little bit.
Play with bot online - click on your nick and there are will be edit profile and trainning with AI