This connects several themes in MTG, like drawing two cards a turn, cycling matters, and graveyard-matters
With just a handful of creatures on the battlefield, Zada makes Expedite look like a better version of Ancestral Recall
I mean, that's obviously ridiculously strong, but I kind of wonder if it's even going to matter much
You have to play some mostly-mediocre cards, you have to get them into your graveyard to start with, you have to replace a draw to get it back and mill yourself and there we have the crux of the problem
Mono-black cards like South Wind Avatar can support these strategies, but its most often used in sacrifice strategies with Blood Artist or Zulaport Cutthroat, or with commanders like Vito, Thorn of the Dusk Rose
They share a spot because Terminate has a more limited range of targets (only creatures, basically), but it only costing 2 mana makes it easy to cast without having to leave too much mana untapped in your turn