Patch notes:

Dominaria United Changes:

Lion Sash has primarily been a midrange card, and didn't quite meet our expectations in terms of play pattern or enjoyment. Guardian of New Benalia will hopefully act as a backup Adanto Vanguard, the 2/2 body is a little smaller than the 3/1 but hopefully the enlist ability will allow it to push through damage that otherwise would get blocked.

Phoenix of Ash has remained in the cube due to it's ability to provide reach to decks that run out of gas, Squee, Dubious Monarch does that same job, at the same cost but is a callback to the classic rabblemaster style of card, seems like an easy swap for testing purposes and we take the more fun/interesting of the two.

Merfolk Branchwalker has existed with the purpose of supporting non-ramp decks which usually appreciate green 2 drops. Quirion Beastcaller will hopefully be more similar to Tarmogoyf than Branchwalker in decks that have lots of creatures. Only requiring a single creature cast to match Branchwalker's stats seems fairly achievable. Maybe the lack of card draw element will make it worse.

Vampire Lacerator has existed purely for blackggro density, the card was clearly the bottom of the pile of creatures and existed as support/filler. Evolved Sleeper is "effectively" a hasty 2/2 for 2, and we've seen the card draw ability be relevant. Feels similar to Knight of the Ebon Legion in that the threat of activation allows it to attack and then you use your mana for other things.

Saheeli, Sublime Artificer is definitely a unique and interesting card with some highlight plays when you are cloning your Glorybringer, but she has been struggling to find a clear home in terms of decks that love her. Hopefully Balmor, Battlemage Captain will fit nicely into UR aggressive/tempo strategies. There is definitely a risk that the UR section will be too easy to fall into while drafting with this card and that deck appears at too high a frequency so we can see a future where this swap is reversed for meta health later.

Balance Change:

Azorious Charm has been fairly uninspiring in the UW section, and under the same logic that UR feels a little too easy to fall into during the draft we are going to hurt UW control a little and instead encourage UW midrange/tempo decks a little more with the inclusion of Spell Queller. This card could see play in control decks but definitely takes on some risk in doing so while being good in decks that don't want to win via attrition.

Mystic Sanctuary is very skill based to execute optimally, and has lead to somewhat repetitive play when paired with Cryptic Command. Otawara, Soaring City should see a bunch of play in most blue decks without having the deckbuilding restrictions or feels bad moments.

Jace, Vryn's Prodigy is only being cut because we were out of ideas for what to cut, but wanted to encourage the rise of blue creature decks we've seen, we felt that Phantasmal Image would support those decks well.

We traded for a foil old border Shardless Agent while drafting the other day and wanted to test it again, Decisive Denial has been a fairly playable card, and I'm not certain this is the right cut over Jolrael, Mwonvuli Recluse but we can always figure out what feels right with a bit of testing.

Steve_man_64 Data Changes:

These were cards we missed during the spoilers, or underrated upon initial evaluation, based on the results of others we are looking to test them in our own environment. Thanks to @SteveMan for the suggestions.

Fact of Fiction has been outdated for a while, having longevity due to how fun it is for both the player casting and resolving it. Occult Epiphany being card filtration whilst also interaction with the board via evasive creatures sounds great.

Caldaia Guardian is a spell that for 2 draws you a card, does 4 damage to the opponent and creates two 1/1 tokens as a floor. With a ceiling of even more.

Brother's War Tests:

Surge Engine seems like a very unique blue tempo card, being an evasive creature that you can use spare mana on at the end of your opponents turn seems great. Vendilion Clique is a card that we know what it does, so it is easy for us to know how it will play when we reflect on these tests later.