Perhaps I do not get what 'all new cards' means but I believe the same issue will remain. If beta packs sell out, people will remain with below-max cards that cannot be leveled up except through market, just like now.
On the other hand, that's just how it is! I don't mind that much we all have the same rules of competition.
The issue isn't really that people will have below-max cards that they can't level up except through the market, it's really having two versions of the same card that are treated as different cards. It's more of a perception and confusion thing than anything else.