I spent pretty much all stream on day two messing with version of Quest Priest and Quest Warlock. Both of these decks have a lot of room to tune – the Priest deck has some really interesting options with the spell mix and how you plan to approach different matchups, especially combo. I ended up with Mojomaster in my last iteration, mostly because he works well with the Seance package I already have for Amara/Talanji and is potentially effective against both Druid and Shudderwock combo decks.
The Priest deck is very good vs Hunter, in my experience, since you have tons of removal for Spellstones. and lots of surviveability. It may want a copy of Psychic Scream vs Deathrattle hunter, but I’ve mostly played vs spell hunter recently.
The Warlock deck seems decent vs aggro, but wants some amount of lifegain vs Hunter, since it can just get run over early and lose to the hero power. That’s why I’m playing the Zilliax/Corpsetaker package. Another option I want to try is Doomsayer and Treachery, since you naturally have Howlfiend, and that can be super strong vs combo decks (while Doomsayer/Treachery can be great vs aggro/midrange).