We should play DXV varietize. For match against two players, randomly pick 30 neutral commons/basics, and 10 class commons/basics per class. You take five minutes to build a deck of whichever class you fancy most, and choose which cards to include or exclude in your build, bo3.
It's a tad complicated, though. What is nice about it is that it balances out the warlock class the same way arena balances out the warlock class, it (somewhat) forces the warlock class to use its subpar class cards to balance out it's abovepar hero power.
Or we can just go with the whole basic common thing. Since the meta is expected to be aggro, we would probably get a little variety in the form of "beats aggro but loses to everything else" decks so it would be ok.