Congratulations on returning to Mythic! Zombies has great potential. The slightest buff can make them the top archetype of Mythic so I am ready to harvest leggies any moment 🙂 I am content with aggro Deception currently, this is why I don't play zombies myself.
Necronomics is an interesting addition to zombies. It gives you an extra turn. For example, on turn 3 + pip, you can drop Cursed Obelisks, Necroscepter, and use god power to get frenzied.
I just checked Necronomics. It looks like a very interesting card, although a bit expensive. Maybe it will be my next target after I collect some GODS.