As noted in the January tier list, this deck is way more powerful than it is popular, maybe because it doesn't have many new toys. That said, this deck is bonkers. I've been on a non-stop win streak since I started playing it in Masters. Heart of the Vault remains one of the best cards in Eternal but the deck finally has the cards around it to make use of the card advantage.
This deck usually stabilizes in time to beat all but the most aggressive aggro draws, and has enough early plays to keep up. Maindeck Shatterglass Mage gives you action against control decks running Avigraft and Permafrost, and SST and Moonstone Vanguard can just win you the game against peaks decks. I think this deck probably loses to control decks running Harsh Rule but there aren't many of those right now.
As far as modifying the deck, Darya has turned out to be great early game and late game, so maybe running more of her. Cauldron Cookbook has been ok-not-great in the main and could probably be replaced, and Purify might be worth running in either the main or the Market.