They... didn't do anything like what I'm talking about, though?
If you do it that way you get a bunch of commons with this weird unconnected text on them and no way to tell that it's a universal theme across the set.
It's just boring if all the face-down cards in the set work that way. You'd have to do a set with at least two of the "mechanic slots" dedicated to face-downs, so you could have regular morphs (or another morph variant) plus this.
Drafting an enemy pairs set is basically the exact same as drafting a wedge set, since you pick two colors to start and then figure out which of two others to spread out into as the packs go on. If you want the two draft formats to feel different you have to move to allied pairs. If it were a shard set, conversely, you'd have to move to enemy pairs.