Foundations Update
Foundations is a huge set with lots of interesting new cards for Pauper. Here are the changes I'm applying to the Cube:
W
+Fleeting Flight -Congregate: although a classic, Congregate can prolong a game by easily netting you 20+ life. This is a bit problematic and I chose to cut it in an effort to make combat damage more relevent. With that in mind, combat tricks are common place in the Cube, and Fleeting Flight is strong for one mana. You can easily eat an opponent's creature or get there for additional damage should you need it.
+Squad Rallier -Kor Cartographer: while fetching a Plains is good, it's less exciting at four mana, even with a 2/2 body. Despite considerations with bounce effects, I'm removing it for Squad Rallier. The number of cards it can find is huge. As a 3/4, it's also a respectable blocker. While I wish the activated ability would cost one less mana, I'm confident this will play better.
U
+Elementalist Adept -Halimar Wavewatch: let's be real, Wavewatch is a remnant of older times. The mana investment to have a 6/6 with Islandwalk is just too much. Although it can block a lot of stuff on the ground by being a 0/6 for four mana, it's still an unexciting card to play. On the other hand, Elementalist encourages proactive gameplay.
+Strix Lookout -Riptide Turtle: one of the reasons why I included the turtle in the first place was so drafters could leverage Vent Sentinel's power. However, taken at face value, the turtle just doesn't do much. Having beefy blockers sure helps, but it also leads to stonewalling games. Strix Lookout is very different and can act like a costly Merfolk Looter.
B
+Infestation Sage -Zulaport Enforcer: as much as it saddens me to remove older cards, this had to go. Much like Halimar Wavewatch, the rate you get for the mana investment is not great. Infestation Sage works well with cards that care about sacrifice like Eviscerator's Insight or Viscera Seer. Plus, it's a great chump blocker.
+Sanguine Syphoner -Audacious Thief: this new vampire has good stats for two mana and a trigger that, while not as good as Creeping Bloodsucker, is still nice to have. The Thief is simply underwhelming most of the time, and you would rather have plain card draw instead.
+Vampire Soulcaller -Briarblade Adept: how many Gravediggers can Black have? Never enough. Kidding aside, this new flier also reminds me of Cadaver Imp, which is also in the Cube. The downside is not being able to block, which I think is fine considering the value you get here. Briarblade's stats are on the lower end, even taking into consideration the ability to shrink a creature on attack. The Encore ability isn't much of a consideration either.
R
+Sower of Chaos -Chainwhip Cyclops: one less toughness for one less mana, but most importantly, the activated ability also costs one less mana.
G
+Apothecary Stomper -Dread Linnorm: adventure is fun because it's basically two spells for a single card. However, paying four mana for a combat trick is rarely worth it. The body is OK at best. On the other hand, Stomper has Vigilance (very valuable in Multiplayer) and can grow to a 6/6 or help another creature get bigger. Also fun with bounce effects and can net you some life should you need it.
+Treetop Snarespinner -Lurking Green Dragon: in the Cube, Green is definitely the anti-air color. The dragon was a discounted flier, but mostly held back as a blocker due to its important restriction. This new spider does an amazing job at defense with the combination of reach and deathtouch. But the icing on the cake is its ability to grow into an even bigger threat, or help beef your other creatures. A well-rounded creature and mana sink!