Theory crafting Ravnica cube
Breaking singleton wherever I see fit. A lot of core color identity cards don't exist in the Ravnica blocks (Most notably there are 0 1-drop and 2 2-drop blue cantrips across all 3 blocks)
Access to 4x each guild gate to enable "Gates Matter" cards and embrace the heavy multicolor influences of Ravnica even if it ruins the flavor of players drafting into a particular guild (May consider changing this to unlimited gates of a single guild in the future)