Thought Vessel is cute but doesn’t do much. Liquimetal Torque makes artifact destruction spells another tool for removal.

I didn't realize how good this card was just by reading it. Farewell does it all. I've never been unhappy with it. I'm ok going up a little in mana cost for a wrath, because I don't want them to be the most efficient in my cube. That said, I think Farewell is better than Cleansing Nova.

Orrery seems like an upgrade to Hedron, and the numbers on EDHRec seem to support that. Orrery has proven it deserves a chance.

I forgot about Boseiju during my NEO update. Force is great. Boseiju fills the same role but can also hit lands, which matters to me since I just added Bazaar and want to make sure it has enough answers.

Soul of New Phyrexia has always been a bit clunky. I never find I have the mana to activate its ability when I need to. And it’s one of 3 colorless 6-drops, an area I’ve been wanting to slim down. Playtest data shows it not being picked or played often either. It has plenty of synergies in the cube, but I think it’s underpowered now. Emergence Zone is a card I want to test now in particular because of the release of Prosper and its synergy with him.

Keiga has been on my mind for awhile because it’s a fine card but doesn’t really fit into any archetype - except maybe Muldrotha value. I think Gearhulk synergizes with more things going on in the cube, and sees more play on EDHREC, so I’m trying it out

This is an easy upgrade. Fewer Oliver Twist mechanics in white, and the good boy helps support enchantress decks. I would replace 3 other white cards with Spirited Companion but I don't want to break singleton. This card looks great.

None of the other cards in NEO have impressed me, so I don't plan to include them unless they get high numbers on EDHREC and are fun to play against.

Some clear improvements.

Dress Down is a like a blue wrath that's proven itself in cEDH. Omen of the Sea is a perfectly acceptable card, but I think Dress Down is going to be a much higher pick.

Fell Stinger is much more efficient than Coffin Queen and better at attacking.

Nightmare Shepherd has tested poorly for my group since players tend to want to recur the same creature more than once, rather than exiling it. Pitiless Plunderer is much better in aristocrats shells - so much so that I considered not adding it to avoid combo shenanigans. But I want to power up the BW aristocrat decks like Teysa Karlov, and it does that.

I was skeptical of Ragavan in this cube environment, but it's great in cEDH and after some testing I'm happy with it here.

Heat Shimmer is what Twinflame wishes it was.

Fairly big change to my Orzhov section because Kaya and Blot Out the Sky ended up underperforming. Kaya was fine but didn't do enough, whereas I'm basically always happy to draw Talisman of Hierarchy. I never ended up casting Blot Out the Sky. In part that's because in the decks where I could play it, I found that I had a lot of artifacts and enchantments that I didn't want to destroy - and I wasn't interested in only creating a few 2/1 fliers. On the other hand while I've been skeptical of Athreos in the past, it has tested fine and I've been happy to draw it. In this case, Talisman and Athreos provide what BW decks want much better than the two cards they're replacing.

Koma is a fine card, and while I thought it would slow games down I've found in testing it tends to be better to keep the coils than tap things down. That said, I think Aesi is better.

Bazaar of Baghdad is worth mention because it's effectively power. For a long time I didn't add it because it has low numbers on EDHRec, and I assumed that reflected narrowness. But recently I learned it might just reflect the difficulty of getting one, because a number of commanders can use the effect. Then I had to test it to see if it would break my cube, and I think it's been fine. It's a powerful card, but I think my cube is a match for it.

The EDHRec podcast episode on mana rocks put me onto Cursed Mirror and Skyclave Relic. I still like Gilded Lotus enough to keep it for now.

On review I realized Red is lacking ways to deal with creatures, so I'm replacing Stolen Strategy with a Chandra that can serve a similar role.

I hear The Scarab God takes over late games, so while it hasn't been amazing in my testing I'm trying it out.

I think UR just wants an Izzet Charm or Prismari Command - I'm adding the cheaper and more widely-played one for now.

Reconnaissance Mission supported a Jeskai tokens deck that has gone fairly undrafted, and the Tuvasa deck doesn't really want that effect, so I'm swapping it out for the much cheaper and more generally-useful Wizard Class.

I have Fyndhorn Elves sleeved up and can't be bothered to swap the two. Fyndhorn is more powerful in my cube. I think it should be fine.

I got negative feedback about the Field addition and I agree with it. It was always a risk adding it, because the more rewards there are for 5c goodstuff the less people get to wheel cards for their color/deck. I thought it might push games to a close faster and be a fun build-around, and that would balance out the risk. But one of my drafters told me it's unfun to play with and against, and that changed my mind.

On second thought, I prefer Garruk to Skyshroud because it goes in more decks and has good synergy with Wild Growth effects.

The cards actually from MH2 here are:
Esper Sentinel
Solitude
Sanctum Weaver
Sythis, Harvest's Hand
Sword of Hearth and Home
Brainstone
Yavimaya, Cradle of Growth

Boreas Charger is worse than it first looked.
I've been wanting to remove Lyra for awhile. Testing will show if replacing a 5/5 flier with a 3/2 kill spell pushes toward too much removal.
Another curator put me onto Silverwing Squadron and it has tested very well. I've been wanting to remove Archon of Coronation because of its damage prevention effect, despite it being white card advantage and a decent blink target. I think the upside for tokens outweighs the downside for other decks.
Akroma's Will has gotten high numbers on EDHRec so I'll test it.
Forsake the Worldly is a fine card but basically a placeholder.
I've gotten tired of Gilded Drake - it's very powerful but not fun to play against.
Teferi is similarly unfun to play against, and doesn't particularly synergize with any archetype. Jace TMS synergizes with a few.
One of my regulars loves As Foretold and Fall from Favor has low numbers on EDHRec and I'm not happy with it either.
Goblin Rabblemaster always seems bad. Loyal Apprentice goes in more decks and has higher numbers on EDHRec and is cheaper.
Curse of Opulence has proven unfun to play against and I want more haste enablers.
I've been counting Fiery Confluence as a wrath since it's used as one most of the time, and Chandra's Ignition is better in that role.
Garruk Wildspeaker is a great card but I only have so many ramp slots and The Great Henge has earned its title and inclusion.
Return of the Wildspeaker has similarly earned an inclusion.
Nahiri is fine but I think there's enough card advantage in Boros now that I can cut it. Gisela is a must-remove card so I'm putting her back in.
I talked about Mindslaver on reddit, tl/dr I'd rather play Emrakul for the same role and decks.
Decided to include Ugin after listening to the Command Zone's podcast about planeswalkers.
Field of the Dead encourages drafting a 5c lands deck, and could just be a defensive card - neither of which I particularly want. But it has high numbers on EDHRec and a drafter suggested it, so I'm willing to test it.

On a side note, with these changes Green is no longer far and away the lowest average CMC out of any color. That should bring its power as a color more in line with the others.
The average CMC of my cube has just gone up from 3.46 to 3.51, so I'll be looking to trim it down in the future.

One last change for now. I think Assemble will help the boros color identity and be a good signpost, as well as pull its own weight.

Talisman is better for casting triple-pips than signet.

Shelldock is good of course, but I've been feeling like I want one more counterspell, and more instants/sorceries in general.

I've been holding off on Mirrormade since my cube doesn't reflect games where 4 players have Sol Ring, but I think it'll still have good targets every game.

I'm more willing to test deathtouch creatures like Mire Triton as time goes on. In my limited testing it's looked much better than Stitcher's Supplier.

Kalitas has been more of a trap for new players than a contributor. I'm excited about Dream Devourer.

Priest of Forgotten Gods asks a lot and is somewhat oppressive when it works, so I'm cutting it for a less-restrictive card advantage engine.

I think Overseer of the Damned vs Abhorrent Overlord is close in terms of offensive power, but the latter was only ever a B+ at best and Overseer more easily fits into decks.

Court of Ambition tested poorly.

Not sure how good Magda will be but I'm up for testing another 2-drop accelerant in red.

I think Goldspan Dragon has proven it deserves a spot. Players haven't been playing Ogre Battledriver, so it goes to the bench for now.

Without Kiki-jiki, Zealous Conscripts hasn't played well. Red artifact decks want what Combustible Gearhulk does, so I'm swapping them.

Hermit Druid and Golgari Grave-Troll do the same job, but Hermit Druid can theoretically go in more decks.

Garruk's Harbinger has been fine, but I want more tramplers, and I think Hydra deserves another shot.

I was persuaded to try Gemrazer. Safekeeper was more-or-less just occupying a slot.

Song of Freyalise tested much worse than it looked like it would.

Underrealm Lich does everything a graveyard-based deck needs - and notably in this format prevents milling out. I've been testing other cards for awhile but I'm coming back to this because I think it'll be the best for BG.

I was persuaded to test Chainer more. I like Stormfist Crusader but I think Chainer will really pop.

I love Vona, but I think Blot Out the sky will do more in the same situations.

I think Kaya will be better for the same decks that want Sorin.

A couple I forgot.

Endless Atlas has been harder than I first thought to activate. Mazemind Tome has proven to be a fine mana sink in Standard.

Basalt Monolith goes infinite with Kinnan, Bonder Prodigy, and Kinnan is a fine commander besides, and Monolith is a mana rock, so I'm cutting it.

I was low on Keeper of the Accord when it first came out but I'm hearing good things about it so am ready to test it.

Capsize and especially Deadeye Navigator are great cards, but since both go infinite with Dockside Extortionist, I have to cut half and I want to keep the red 2-drop, since red is struggling for playables in that section. I've liked Docent of Perfection in regular EDH and am curious to see if it can hold its own here, especially since it and Shark Typhoon both support casting spells. I think Into the Story will be good too as a 4-mana instant draw-4.

I realized Seasoned Pyromancer does everything red wants, so I'm going to test it over the rarely-drafted Hanweir Garrison

I looked at the math on wraths in my cube again and decided I needed to cut 4. In each color that had 2, I chose to keep the more expensive wrath to make it a little harder to cast them. So I cut Winds of Abandon and kept Cleansing Nova, cut Toxic Deluge and kept Damnation, cut Blasphemous Act and kept Fiery Confluence/Chandra, Flamecaller.

Vedalken Orrery and Leyline of Anticipation both combo with Seedborn Muse, and I'm finding that having to deal with both of them is a little too much - if the player playing them is in green, players can't let either stick around. I want to keep Leyline to support enchantress decks, and I've never really been impressed with Orrery, so I'm cutting Orrery.

As of now, all basics in my basic land box are snow basics to support Arcum's Astrolabe. I'll be watching to see if it appears in 5 color decks, since it doesn't work with any of the nonbasics in my cube and isn't particularly useful for the Sovereign's Realm player.