The release schedule is based on a lot of factors. Some of the biggest are competing products (even if they're not in the same industry) and school schedules for high-school and college-aged kids (one of MTG's biggest demographics). The fall set comes out just as school is starting and the weather is changing. That means less competition from outdoor activities and fewer people traveling (thereby being more likely to attend events or even play at home).
The holidays (November, December) are typically slower, because MTG has to compete with tons of other products that are given as gifts.
The spring set typically will release during the window where most students are on Spring Break which will give a boost to the number of available players.
The late-spring set seems to hit a bit before people start going on summer vacation. The summer sets are typically the lowest selling of the year, which is likely why they'd put the core sets in that slot (they're likely to sell worse anyway since they're mostly reprints). Since people are going on vacation and doing outdoor activities, it dilutes the player base a bunch.
Cool concept, but Judgment Day doesn't really work within the rules. The wording you'd need to make the damage ability works would probably be too long for the text to fit on an actual card. Even if it's not, it reads a bit strangely. "Each creature has "When a creature dealt combat damage by this creature this turn dies, put a judgment counter on this creature.""
A workable alternative might be something like this:
Judgment day enters the battlefield with X judgment counters on it.
Whenever an attacking creature deals combat damage, move a Judgment counter from ~ onto that creature.
When ~ has no Judgment counters on it, sacrifice it. If you do, destroy all creatures will judgment counters on them.
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Go With The FlowR Sorcery
As an additional cost to play Go With the Flow discard X cards.
Exile the top X cards of your library. Until the end of turn, you may play those cards.
Cool concept, but Judgment Day doesn't really work within the rules. The wording you'd need to make the damage ability works would probably be too long for the text to fit on an actual card. Even if it's not, it reads a bit strangely. "Each creature has "When a creature dealt combat damage by this creature this turn dies, put a judgment counter on this creature.""
A workable alternative might be something like this:
Judgment day enters the battlefield with X judgment counters on it.
Whenever an attacking creature deals combat damage, move a Judgment counter from ~ onto that creature.
When ~ has no Judgment counters on it, sacrifice it. If you do, destroy all creatures will judgment counters on them.
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Go With The FlowR Sorcery
As an additional cost to play Go With the Flow discard X cards.
Exile the top X cards of your library. Until then end of turn, you may play those cards.
Tax Collection seems like a fine card mechanically, though the Wall should probably have defender. The flavor doesn't really make much sense at first blush; the counterspell part does, but it's unclear what a wall has to do with collecting taxes. I assume the idea is that's what the taxes went toward. If that's the case, I think a delayed trigger makes it read a lot better. "Counter target spell unless its controller pays 2. If that player does, put a 0/3 colorless Wall artifact creature token with defender onto the battlefield at the beginning of the next end step." Flavor text would obviously help with the concept as well.
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Mystifying Mimic2WU Creature - Shapeshifter (R)
You may have Mystifying Mimic enter the battlefield as a copy of any creature on the battlefield, except it gains "3WU: Exile this creature, then return it to the battlefield under your control."
0/0
Splintering Lie feels off in several ways. The default case isn't a card you'd ever want to play. 3 mana for a 1/1 with no evasion or other notable abilities is far below the curve. When it feels like you have to kick something to make it useful, it defeats the purpose of kicker. but, even kicked, this feels pretty weak. You can pay 5 mana for a 2/2 that leaves behind a 1/1 or 7 mana for a 3/3 that leaves behind two 1/1s. Compare to Carrier Thrall or MaUSolEUmGUaRd
Lastly, this card feels more GU or even mono-G than mono-U. Blue typically copies other creatures, while green will make copies of itself (see Giant Adephage, Sprouting Phytohydra, Spawnwrithe & Essence of the Wild). Blue also typically gets its card advantage via card draw, not creature replacement.
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Council of Dusk1UB Creature - Vampire Advisor 1UB, T, Pay X Life: Scry X, then draw a card.
1/4
Unceasing Growth is an interesting effect, but I've never really been a fan of Epic as a keyword. In this case, one board wipe will mean a game loss unless you have non-spell based way to make tokens. It does lead to interesting deck-building decisions.
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Call the ConjurersUR Instant
Put a 1/1 blue and red Wizard creature token with Flying and Prowess onto the battlefield.
Flashback 2UR(You may cast this card from your graveyard for its flashback cost. Then exile it.)
Just a heads up; the way double-faced cards appear in packs in SOI is different than in the original Innistrad block. Every pack has a common or uncommon DFC that replaces a common. 1 in 8 packs has a Rare or Mythic Rare DFC that replaces another common (in addition to the Common/Uncommon DFC). With that in mind, the "booster" field should look something like this:
Cryptic ClimateWWUU Enchantment
Flash
When Cryptic Climate enters the battlefield, tap each creature and draw a card.
Creatures enter the battlefield tapped.
Reverted Shambler seems fine for constructed, but is probably too strong for limited. If this comes down on turn 2 and your opponent doesn't have a follow up, it gets out of hand very quickly. It's also a bit strange with some of the cards that check for "non-human" transformation, like Immerwolf and Cult of the Waxing Moon
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Determined Pragmatist2B Creature - Human Warrior
Survivor 1B(When this dies you may pay 1B and sacrifice another permanent. If you do, return this to the battlefield tapped.)
Each other creature you control has Survivor. Its Survivor cost is equal to its mana cost.
3/2
Philanthropy2WW Creature - Incarnation
Flying, Lifelink
Whenever you gain life, distribute that many +1/+1 counters amongst creatures you don’t control.
5/5
Emrakul, the Vast Devourer has flavor, gameplay and templating issues.
Flavor - Eldrazi are native to the Blind Eternities (the space in between planes) so it doesn't make sense for one to have a planeswalker spark.
Gameplay - The -3 ability is severely overloaded. It needs to do less and be a lot more powerful given the mana cost. Speaking of which, the mana cost is entirely too restrictive and feels odd for the sake of being odd. Needing every color of mana and 5 colorless mana is pretty contradictory from a deck-building standpoint.
Templating - "Exile target card," is far too broad. Since it does specify a zone or card type, it can literally target any card, even cards in hidden zones or exile. "Activate Emrakul's +1 targeting the 32nd card from the top in your library," would be a legal way to play that ability, for example. The card text for the -3 ability alone wouldn't even fit on a normal-sized card.
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Back Alley Brawler2R Creature - Human Rogue
As long as Back Alley Brawler is equipped, it has haste and menace.
3/2
Scodrid, God of Disharmony is an example of overloading a design. This is like 4 or 5 cards squeezed into one. Ignoring the fact that all that text could never fit comfortably on a card, this card requires far too much bookkeeping and would likely lead to analysis paralysis.
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Propaganda PeddlerUU Creature - Human Rogue
Skulk
When Propaganda Peddler deals combat damage to a player, tap target creature that player controls. That creature doesn’t untap during its controller’s next untap step.
1/2
Velsir, Illusive Mindknight feels a bit weak. His current ability line up leads to awkward play patterns. If you +1 him right away, it has no real effect on the game state. If you -3 him right away, you'll often want to avoid doing +1 on the following turns, otherwise you'll lose the permanent you've taken control of. Changing the sequence to +1 then -3 leads to a similar situation. Activating his +1 loses you the stolen permanent and activating his -3 loses you both permanents, since he goes to the graveyard. So either you activate his -3 immediately and then he sits there doing nothing for a long time; or you activate his +1 multiple turns in a row until he can do something worthwhile. Either way, he's taking a lot of time off.
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Augur of KeranosUR Creature - Elemental Shaman
Prowess
When Augur of Keranos deals combat damage to a player, you may pay UR. If you do, return target instant or sorcery card with converted mana cost X or less from your graveyard to your hand, where X is Augur of Keranos’s power.
1/3
The holidays (November, December) are typically slower, because MTG has to compete with tons of other products that are given as gifts.
The spring set typically will release during the window where most students are on Spring Break which will give a boost to the number of available players.
The late-spring set seems to hit a bit before people start going on summer vacation. The summer sets are typically the lowest selling of the year, which is likely why they'd put the core sets in that slot (they're likely to sell worse anyway since they're mostly reprints). Since people are going on vacation and doing outdoor activities, it dilutes the player base a bunch.
A workable alternative might be something like this:
Judgment day enters the battlefield with X judgment counters on it.
Whenever an attacking creature deals combat damage, move a Judgment counter from ~ onto that creature.
When ~ has no Judgment counters on it, sacrifice it. If you do, destroy all creatures will judgment counters on them.
---
Go With The Flow R
Sorcery
As an additional cost to play Go With the Flow discard X cards.
Exile the top X cards of your library. Until the end of turn, you may play those cards.
A workable alternative might be something like this:
Judgment day enters the battlefield with X judgment counters on it.
Whenever an attacking creature deals combat damage, move a Judgment counter from ~ onto that creature.
When ~ has no Judgment counters on it, sacrifice it. If you do, destroy all creatures will judgment counters on them.
---
Go With The Flow R
Sorcery
As an additional cost to play Go With the Flow discard X cards.
Exile the top X cards of your library. Until then end of turn, you may play those cards.
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Mystifying Mimic 2WU
Creature - Shapeshifter (R)
You may have Mystifying Mimic enter the battlefield as a copy of any creature on the battlefield, except it gains "3WU: Exile this creature, then return it to the battlefield under your control."
0/0
Lastly, this card feels more GU or even mono-G than mono-U. Blue typically copies other creatures, while green will make copies of itself (see Giant Adephage, Sprouting Phytohydra, Spawnwrithe & Essence of the Wild). Blue also typically gets its card advantage via card draw, not creature replacement.
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Council of Dusk 1UB
Creature - Vampire Advisor
1UB, T, Pay X Life: Scry X, then draw a card.
1/4
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Call the Conjurers UR
Instant
Put a 1/1 blue and red Wizard creature token with Flying and Prowess onto the battlefield.
Flashback 2UR (You may cast this card from your graveyard for its flashback cost. Then exile it.)
Instant
Target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.
Next:
Dim the Lights
Geistbusters
Olenvahs, Repentant Demon
Enchantment
Flash
When Cryptic Climate enters the battlefield, tap each creature and draw a card.
Creatures enter the battlefield tapped.
Next: 1UR
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Determined Pragmatist 2B
Creature - Human Warrior
Survivor 1B (When this dies you may pay 1B and sacrifice another permanent. If you do, return this to the battlefield tapped.)
Each other creature you control has Survivor. Its Survivor cost is equal to its mana cost.
3/2
Creature - Incarnation
Flying, Lifelink
Whenever you gain life, distribute that many +1/+1 counters amongst creatures you don’t control.
5/5
Next:
Persuade
Nahiri's Awakening
Needlewing
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Back Alley Brawler 2R
Creature - Human Rogue
As long as Back Alley Brawler is equipped, it has haste and menace.
3/2
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Propaganda Peddler UU
Creature - Human Rogue
Skulk
When Propaganda Peddler deals combat damage to a player, tap target creature that player controls. That creature doesn’t untap during its controller’s next untap step.
1/2
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Augur of Keranos UR
Creature - Elemental Shaman
Prowess
When Augur of Keranos deals combat damage to a player, you may pay UR. If you do, return target instant or sorcery card with converted mana cost X or less from your graveyard to your hand, where X is Augur of Keranos’s power.
1/3