Lets look at how the mechanic came to be, what it was intended to do, and why it likely wont be reappearing any time soon
In the Commander variant, a double-faced card's color identity is determined by the mana costs and mana symbols in the rules text of both faces combined
If you grew up with Pokemon Black & White, this is the set
Its nothing fancy, but playing this on turn one allows you to play a four-cost card on turn two - and its rare that such a speedy start to a game doesnt result in a massive advantage
+1: Until your next turn, you may cast sorcery spells as though they had flash
In general the power level of the set seemed to have been cranked up to eleven, with plenty of cards able to cheat on resources like Fires of Invention or Once Upon a Time