Art by Jaime JonesWelcome to my Dominaria set cube. The cube is designed to be an introductory experience for players new to Magic: the Gathering draft. Dominaria contains classic fantasy themes, historic Magic characters and places, and intuitive mechanics without too much complexity. It's also one of the best draft formats in Magic's history, even for seasoned players. The cube is meant to replicate the retail draft experience just as if you were cracking a fresh box of booster packs.
Card ratios were modeled after the theories in the following article,
specifically Method 1: Retail Replication.
https://strategy.channelfireball.com/all-strategy/mtg/channelmagic-articles/cube-design-set-cubes/
To create packs commons, uncommons, and rares/mythics should be kept separate and seeded into packs (10/3/1, respectively). Real Dominaria booster packs have complex collation that ensures a legendary spell is present in every pack. Adding 3 random uncommons and 1 rare/mythic won't guarantee a legendary, but packs should average 1+ legendaries over the course of a draft. Try opening some sample packs to get a sense of the legendary frequency you should expect.
Oath of Teferi and Damping Sphere are do nothing cards in draft. Teferi, Hero of Dominaria was cut for power reasons. Mox Amber is fine but I don't own one and it has a very high cost-to-impact ratio. It doesn't feel worth the price to add. Jodah, Archmage Eternal is fine just as a reasonably costed flier but the ability seems irrelevant. It felt weird to include.