I would try to design your set so that the decks that use your reactive cards don't suck too hard to cascade into so that people still have lots of choices in draft. If you do a 2/2 for 4 cascade and it turns out that's really good and people tend to draft decks where they get a couple of those, one of the others, and then change their drafting algorithm to "Built to Smash, Cancel, and Skywhaler's Shot are blank for me" you are reducing draft decision trees more than you need to. Replace Cancel with some kind of Unsubstantiate, Built to Smash with Titan's Strength or somesuch, etc.
As Unnamed Ballad enters the battlefield, each player names a permanent card. Spells with that name can't be cast.
When Unnamed Ballad enters the battlefield or is turned faceup, draw a card and for the rest of the game, permanent cards gain Megamorph. The Megamorph cost is equal to the mana cost.
As indicated by the reminder text on Bomat Courier, players can't look at facedown exiled cards they own unless a card ability says they can. Thoughtlock Machine will need rules text, not reminder text, that says "Players can look at facedown cards they own exiled by Thoughtlock Machine".
I've looked back at the cards from many a sealed event I did well in early in the season and have said "Wow, I top8ed but I was running a really bad card."
Which I think goes to show that being able to make good in game plays and being a generally good magic player can mean a lot.
I would encourage you to just played sealed as much as you can and not worry about whether it's possible for those sealeds to have aether revolt in them because knowing when to block, when to attack, and when to bluff transcend formats.
Uniska of the New MoonB
Legendary Creature — Vampire Cleric (R)
Deathtouch
At the beginning of your upkeep or when Uniska enters the battlefield, each creature target opponent controls gains "must block if able" until end of turn unless that player has it gain "can't block" until end of turn.
"It's not that we don't know which night of the month the village most dearly needs our protection. It's that we do."
1/1
I think Legendary is a bad drawback for cards since it doesn't add decision intensity to the decision on whether to include the first copy, but there is nothing unique about how lands interact with that. So I don't really get the reason to complain about OP. Legendary is an equally ineffective deterrent for including the first copy of Thalia, Heretic Cathar and for including the first copy of greenland five, but with both there is a quality-of-life benefit for Standard and Limited environments (restricted ability to deny blockers while curving out aggressive creatures and restricted ability to chain lucky pairs snagged in a sealed pool or draft, respectively).
If you mean that someone shouldn't feel like Legendary isn't the only drawback going on with the card and are trying to point out WotC wouldn't print a 3/2 first strike for 2W alongside Thalia in a set (which is true, they wouldn't, while they would turn around and print that card elsewhere in a heartbeat), then sure, you're right, but you're trying to blame OP for creating an entire environment for which he is only proposing a piece. By the law of charitable judgments, I assume OP would design the rest of his set to have at least punishment for cards lacking a basic land type (like Corrupt or Prairie Stream), and then the other downside remains meaningful in Limited, Standard, and of course Eternal where Blood Moon and Back to Basics hit tables.
I know land destruction can be boring, but with some work it can be fun too. What about changing the red land to "each player sacrifices a tapped nonbasic land" if you want to play around with that one?
The answer lies in the next two rules after the ones you quoted:
514.3. Normally, no player receives priority during the cleanup step, so no spells can be cast and no abilities can be activated. However, this rule is subject to the following exception:
514.3a. At this point, the game checks to see if any state-based actions would be performed and/or any triggered abilities are waiting to be put onto the stack (including those that trigger “at the beginning of the next cleanup step”). If so, those state-based actions are performed, then those triggered abilities are put on the stack, then the active player gets priority. Players may cast spells and activate abilities. Once the stack is empty and all players pass in succession, another cleanup step begins.
And this rule:
703.3. Whenever a step or phase begins, if it’s a step or phase that has any turn-based action associated with it, those turn-based actions are automatically dealt with first. This happens before state-based actions are checked, before triggered abilities are put on the stack, and before players receive priority.
So, the turn based actions would be dealt with prior to State Based Actions doing anything which means you would both discard to hand size and remove damage before state based actions being checked.
Wow, I've never been exposed to this part of the rules before.
As a follow up, say the card Python discards is a Fiery Temper. He puts it in exile and temporarily has a 7/7 Aeon Chronicler with 7 damage marked on it immediately after completing 514.1 Then he removes all damage from it in 514.2, and it becomes a 7/7 with no damage marked on it. Then 514.3a generates an exception and allows python to cast Fiery Temper targeting his own Aeon Chronicler, but it doesn't die, now it's a 7/7 with 3 damage, damage taken AFTER the remove-all-damage housekeeping. But that doesn't let the damage sneak into next turn, because 514.3 generates another cleanup step that will remove the damage.
See what power you can raise 2 to.
Enchantment (M)
As Unnamed Ballad enters the battlefield, each player names a permanent card. Spells with that name can't be cast.
When Unnamed Ballad enters the battlefield or is turned faceup, draw a card and for the rest of the game, permanent cards gain Megamorph. The Megamorph cost is equal to the mana cost.
As indicated by the reminder text on Bomat Courier, players can't look at facedown exiled cards they own unless a card ability says they can. Thoughtlock Machine will need rules text, not reminder text, that says "Players can look at facedown cards they own exiled by Thoughtlock Machine".
Replique
U
Instant (U)
Put a 1/1 artifact creature token onto the battlefield. It gains a creature type of your choice.
Which I think goes to show that being able to make good in game plays and being a generally good magic player can mean a lot.
I would encourage you to just played sealed as much as you can and not worry about whether it's possible for those sealeds to have aether revolt in them because knowing when to block, when to attack, and when to bluff transcend formats.
Uniska of the New Moon B
Legendary Creature — Vampire Cleric (R)
Deathtouch
At the beginning of your upkeep or when Uniska enters the battlefield, each creature target opponent controls gains "must block if able" until end of turn unless that player has it gain "can't block" until end of turn.
"It's not that we don't know which night of the month the village most dearly needs our protection. It's that we do."
1/1
I'm sure that's impossible.
Mine will always be Kiss of the Amesha.
If you mean that someone shouldn't feel like Legendary isn't the only drawback going on with the card and are trying to point out WotC wouldn't print a 3/2 first strike for 2W alongside Thalia in a set (which is true, they wouldn't, while they would turn around and print that card elsewhere in a heartbeat), then sure, you're right, but you're trying to blame OP for creating an entire environment for which he is only proposing a piece. By the law of charitable judgments, I assume OP would design the rest of his set to have at least punishment for cards lacking a basic land type (like Corrupt or Prairie Stream), and then the other downside remains meaningful in Limited, Standard, and of course Eternal where Blood Moon and Back to Basics hit tables.
________________________________________________________________________________________________________________
I know land destruction can be boring, but with some work it can be fun too. What about changing the red land to "each player sacrifices a tapped nonbasic land" if you want to play around with that one?
Wow, I've never been exposed to this part of the rules before.
As a follow up, say the card Python discards is a Fiery Temper. He puts it in exile and temporarily has a 7/7 Aeon Chronicler with 7 damage marked on it immediately after completing 514.1 Then he removes all damage from it in 514.2, and it becomes a 7/7 with no damage marked on it. Then 514.3a generates an exception and allows python to cast Fiery Temper targeting his own Aeon Chronicler, but it doesn't die, now it's a 7/7 with 3 damage, damage taken AFTER the remove-all-damage housekeeping. But that doesn't let the damage sneak into next turn, because 514.3 generates another cleanup step that will remove the damage.
That's all correct right?