I'm new to the game, but I'd prefer if instead of rerolling both cards, you could reveal 2 more cards (leaving the previous 2 there) or you can reroll cards individually twice instead so you can choose between a pragmatic option (gargoyle -> hellfire) and something that changes strategy more.
It would also be nice to add a bit more options for deck management. Like a card bank and/or a way to get multiple cards in one selection. As-is certain options don't make sense when you get them early on. There are probably interesting ways of dealing with that, though I would probably make it something that works in the early game (block discarding/splitting or some buff(s)/alternatives to Maw).