Running it in decks with more than three colors feels dicey
Its casting trigger exiles the top half of an opponents library, quite literally, cutting half their cards out of the game
They are legendary
Its one of Magics most powerful creature types, each with their own take on what it means to be an all-powerful godly being
Having a second enchant creature on the list is clearly a sign that these decks played things pretty safe as far as two-player games of Magic go, but Grim Reapers Sprint incentivizes you to cast it at a point in the turn where you would expect your opponent to have already fired off their removal spells
Like most Magic: The Gathering cards, the value of Crucible of Worlds depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Kaladesh Inventions)