Student of Warfare -> Guardian of the Great Door
Reasoning: Student of Warfare is usually too slow for this cube, and there isn't enough proliferate to justify leveling being included. Guardian, on the other hand, plays nicely with all the artifact tokens being generated as well as the low mana value reanimation spells.
Sylvan Library -> Smuggler's Surprise
Reasoning: Sylvan always takes so long to resolve, feels like a color pie break, and only plays in the space of "card draw matters." Smuggler's Surprise on the other hand: gives green game against countermagic and removal and also plays into the graveyard synergies.
Quest for the Necropolis -> Unearth
Reasoning: Quest is way too slow, and can be destroyed without allowing an instant speed activation.
Psychic Frog -> Scuttling Sentinel
Reasoning: Psychic Frog warps games around itself, and dominates the entire game. While it does play well with other synergies in the cube, that's not how it sees the most success. Scuttling Sentinel provides some more protection for creature-heavy decks against the really efficient removal here and fits into the flicker archetype.
Other Addition ExplanationsReasoning: Board stalls are a problem in the cube right now. My hope is that increasing the density of wraths makes control more viable and increases the likelihood that at least one wrath is seen in every draft.
Reasoning: Another nice target for both Urza's Saga and Stoneforge Mystic.
Reasoning: Coco is probably too good here, because everything is so low on the curve. However, it is another way for green to play at instant speed, and it applies some nice deckbuilding restrictions when drafted.
Reasoning: I am forever on a quest to make "spells matter" viable. This increases the likelihood that at least one of Bedlam Reveler and Murktide Regent are available in any given draft.
Other Removal ExplanationsReasoning: This always felt like bait in the cube. Cards are generally low curving, lands are already painful, and splashing lots of colors is encouraged.
Other Changes