Its imperfect interaction that requires you to have big creatures on the board, and its vulnerable to instant-speed removal or combat tricks
Many Magic sets and Commander pre-con decks have made the Zombie tribal deck scarily effective, and anyone who wishes to build a Zombie tribal deck in Commander or in casual MTG is encouraged to pick the tribe's best creatures and go from there
Blasphemous Act, Decree of Pain, Feed the Swarm, Languish, Living Death, and Bitter Downfall account for six removal spells for creatures alone in this deck
Its pretty much just a more expensive Night's Whisper or a worse Read the Bones
Unfortunately, I could see a sharp decline in the amount of play Champion of Wits sees once Elder Deep-Fiend rotates out of the format
What's important about the design of this card, however, is that it can also sacrifice itself, giving you an easy way to add two card types to your graveyard