I'm really into the competitive side of the card game, but don't know any history of it
Nguyen tells me that these decisions are generally more art than science, taking into account a cards desirability in the playerbase, the bandwidth they have for coordinating artists and other resources, what each individual drop might call for thematically, and more
The short answer is that it depends on the format
Once per turn: You can send 1 "Zodiac" monster from your Deck to the GY, then target 1 monster your opponent controls
It's not over until the last draw
For just three mana, Out of Time sweeps the battlefield of creatures, phasing them out for turns equal to the number of time counters on it