The winrate dropped off a little at rank 7, but I think part of that was me playing poorly after 50 games with the deck today and doing something else at the same time. I changed the list some at the very end, I'm not sur eif the changes will help or not.
Mistress of Mixtures
Northshire Cleric (this used to be potion of madness)
Twilight Welp
Zombie Chow
Netherspite Historian
Shadow Word: Pain
Wyrmrest Agent
Brann Bronzebeard
Dark Cultist
Deathlord
Kabal Talonpriest
Shadow Word: Death
Velen's Chosen (used to be Shadow Madness)
Kazakus
Shifting Shade
Twilight Guardian
Azure Drake
Blackwing Corruptor
Drakonid Operative
Holy Nova
Raza the Chained
Sludge Belcher
Book Wyrm
Holy Fire
Justicar Trueheart
Reno Jackson
Sylvanas Windrunner
Chillmaw
Confessor Paletress
N'zoth the Corruptor
Edit: Hitting the gold cap playing this deck all day is pretty mentally exhausting. That's a lot of thought and hard games. You can see some games with it if you want because I streamed most of it. Below is the middle VOD (it's split in three, I got a BSOD that split first, then the stream randomly dropped later). I'm not that entertaining, but you can see the deck play out