While other characters like the Floodborn Mother Gothel released in Shimmering Skies will still be preferred for most decks, Emerald/Amethyst decks that specialize in exerting opposing characters will be able to benefit massively from this ability, enabling them to effectively clear the board if played correctly
It costs 4 mana for the cards that care about that, it creates a Wizard token for the wizard deck, and it draws you into more cards
Zellix is a horror creature with hivemind that creates a 1/1 horror whenever one or more creatures are milled
Also, I wouldnt discount the discard ability, which could provide some slow consistent value in a deck helmed by Ravos, Soultender or any deck with a lot of graveyard-to-hand recursion theme
Im expecting a lot of wonderful weirdness out of this one
EDH is probably the most played format at the store