Typically, having very few cards in your library is a nightmare scenario, so cards like Doomsday or Leveler are trying to enact a harsh penalty that turns out to be a boon
Booster Box (Magic Battle for Zendikar | Magic Cards) prices are based on the historic sales
While the play patterns around cards like Uro, Oko, and Arcums Astrolabe are far from my favorite, these cards dramatically altered the balance of power in the format without just adding or aiding linear combo a rare feat in Moderns history
Targets are chosen for that spell before you choose another player to help you pay for it and before that player has committed any mana to doing so
In fact, we ranked it as number one on our list, with the caveat that it was close between Prismari and Witherbloom
However, there are a lot more artifacts to get back in the format, and the milling ability is actually upside in most decks