Sever the Bloodline for
Oubliette, here it is an upgrade from an exile effect for an exile effect. Oubliette was good with Zur but Sever the Bloodline is more universal as it still exiles (important vs. indestructible creatures), answers swaths of tokens, and has flashback.
Dark Hatchling for
Abyssal Specter, Abyssal was a relic of when black cared about discard, but in a multiplayer game discard is much less effective so murder was the case that they chose. While the jump from 4 to 6 is a bigger jump than normal turn 6 is really when creatures need to start dying.
Ghost Quarter for
Sun Droplet, no one used Ghost Quarter and the Sun Droplet seems like a fun card.
Perilous Myr for
Arcbound Crusher, Perilous Myr is being removed because creatures that have effects leaving the battleground are being removed and while Perilous Myr is good with Glissa the Arcbound Crusher should be bigger and better. Also while generally I try to keep the 'honey comb is big' to creatures that have some defense mechanism I think the modular fulfills that need.
Spawning Pit for
Peace Strider, Spawning Pit is a generally good card full of utility however because cards like Arcbound guys, Sphinx Summoner, Master Transmuter, etc. more artifact creatures were needed.
The following are being added to aide in the artifact creature boost as well as to take away some from the mono-colored and increase the colorless in the cube.
Stitch Together for
Pierce StriderCompulsive Research for
ViselingSpirit Cairn for
Arcbound SlithMitotic Slime for
Mirror GolemStromkirk Noble for
Death-Mask DuplicantSeedguide Ash for
Genesis, very similar to the Perilous Myr situation about leaving the battlefield effects being removed. I consider land ramp a much more valuable use especially with green and green has a lot of resources that are good with the graveyard but Genesis is just a bomb.
Naturalize for
Algae Gharial, green has lots of artifact and enchantment removal and doesn't really need this card and a big honey comb with shroud is never a bad thing.
Adamaro, First to Desire vs
Firewing Phoenix, Adamaro is a good 6/6 or 7/7 on turn three, but that's all he is and red is transitioning (slower than I would like) over to a number of repeatable/recurrable cards that should give red the longevity that it needs.
Braid of Fire vs
Sandstorm Eidolon, Braid of Fire was too slow and the recurrable creature every time you cast your Commander or another multi-color creature was a good option.
Burning Palm Efreet vs
Aladdin, Aladdin is so underrated and with the increase in artifact creatures his ability to steal them was more powerful than the Efreet's ability to clear the skies.
Archon of Justice vs
Springjack Shepherd, another exit the battlefield effect being removed. The Shepherd should do some work with overrun cards, or just Marshal's Anthem and Elesh Norn.
Knight of Meadowgrain vs
Soul's Attendant, one less mana and a lot more life gain. The Knight is good but double white is also harder to cast.
Mistmoon Griffin vs
Mass Calcify, another exit the battlefield effect being removed. Calcify seems good at being a mostly one sided wrath.