I agree that this change will probably lead to economy problems. It may (or may not) work for now that we have lots of boosters opened but after the reset and launch there will probably be issues with card supply. You can't have whales in this game (which I am fine with) who open enormous amounts of boosters and so supply the market.
I think that 1 booster/30 minutes of gameplay is probably a bit much but instead of totally removing the daily booster, I'd rather have a system where you can afford 1 booster after ~1 hour of play and then additional tiered rewards, similar to the current a