So I've given some thought to this topic, and though my first response was in the direction of "here is why I think Clarion Spirit is great and other mechanics with the same traits", it took me longer to think about "what mechanics are educative to players". Let me try to organize my thoughts:
Didactic Cards and Mechanics
I'm going to tentatively call the design device we're talking about
didactic cards and mechanics. Didactic cards and mechanics
explicitly state what is good in this environment (signposting). If sacrifice is a supported archetype, put payoffs that are explicit about it:
Mayhem Devil is didactic, but
Priest of the Blood Rite isn't. If tricolor decks are good, tricolor cards like
Mantis Rider and
Temur Charm are didactic. If it's a fast environment in which aggro is good, some didactic mechanics are raid, pack tactics, boast, unleash, bloodrush, can't block, and must attack.
Traps
As important as having didactic cards that signal to the right direction (true signposts) is
avoiding false statements about what is good (traps or false signposts). If you add
Rattlechains to a cube that has few spirits, it alludes to a deck that's not there, constituting a trap. Similarly, having an archetype that is at a lower power level than the other archetypes or the good-stuff (which is super common) is also a trap. You promised the player that the archetype was a legitimate way to win, but it can't compete. I wrote a post on false signposts last year:
https://desolatelighthouse.wordpres...d-paragon-and-false-signposts-one-card-a-day/
Pros and Cons of Didactic Cards
Didactic cards and mechanics are a tool that brings multiple advantages. Most importantly, they help novice players that haven't come across that sort of environment to more quickly grasp it and have a better deck in their first try, instead of having to fail spectacularly before they learn something. They also signal to players of all skill levels what is good in that environment. Didactic cards serve as a test that your vision is working out - if the didactic card turns out to be a trap, your vision of the environment isn't aligned with the reality of what's good in the environment. Didactic cards can also reduce the inherent familiarity delta between the cube design and other players, but that's contingent on them not being traps. More generally, didactic cards reduce the delta between a player that is familiar with the list and one that isn't.
Like everything, didactic cards and mechanics have negative sides. Players may feel obliged to do what the cards say and "play aggro" or "draft many colors" or "avoid splashy creatures". Some players want to do their creative thing, or enjoy a particular type of deck (say, control), and if you force them into the best strategies in your cube, it can feel bad to them. For many players, exploring an environment and finding the best strategies is a more rewarding experience if there is less signage. Didactic cards do not often cross-polinate between multiple archetypes too (though Clarion Spirit is a nice exception).
A broader feature/issue with didactic cards is that they deepen and solidify the designer's vision and beliefs. That is both good, neutral and bad, but it's good to know. A possible issue is that it creates false beliefs about what is good in an environment, though you'll only find out when someone breaks it, which may be never.
Cube Spectrum: Didactic x Uncharted
Overall, you could say there are cubes that fall on the "didactic" side of the spectrum, with more explicit signage, and cubes that are on the "uncharted" side of the spectrum. Good "didactic" cubes will reduce the skill difference between players and present a more approachable environment, while and good "uncharted" cubes will give them a puzzle consisting of building something great from a bunch of parts. I say it's a spectrum because those two features are somewhat at tension with each other. One can layer a cube so that it has a bit of each, and I would consider that to be in the middle of the spectrum. For example, in original Innistrad, there are explicit archetypes, but Spider Spawning is quite hidden. There is no enchantment that says "Spiders you control have deathtouch. When ~ ETBs, mill four cards."
https://magic.wizards.com/en/articl...ited/remembering-innistrad-limited-2016-03-08
Typical environments
@landofMordor asked specifically about didactic cards for "kinds of Magic strategy that might get discussed in Next Level Deckbuilding, Limited Resources, or another similarly universal resource." I haven't read the first yet, but I listened to quite a bit of LR, Lords of Limited, and limited Twitch streamers. They have different views of what is good and how to approach environments, and even in Next Level Magic Chapin says:
Often, you hear things like “Birthing Pod is game over,” or “I got mana-screwed, then mana-flooded,” or “It's all about tempo and mana curve,” or “Just draft removal and bombs,” or “Just pick your colors and stick with them.” Sometimes you're even the one saying them. These narrow observations are surface-level, and reveal only a small part of the picture of what is going on.
Fixed perspectives like these are weak compared with a reasoned, multilayered, systematic analysis.
I'm skeptical that single didactic cards can really convey the nuance present in limited environments, especially the well balanced ones. Good game design, in my opinion, is based on tension. If it's obvious you should attack all the time, you are forced to do it, so you're watching the game itself playing out rather than actually playing the game. That's why I believe the best way to approach didactic cards is to add ones that have tension with one another:
Delver of Secrets,
Wrath of God,
Goblin Chieftain. The top end of the power band is where one should be most careful about maintaining tension.
Lessons I can think of that are commonly useful for beginner players and apply over a breadth of formats:
- Draft bombs highly
- Draft removal highly too
- Play good cards
- Play creatures
- Play a good curve (though what is acceptable varies a lot from format to format)
- Keep synergies in mind, but evaluate them considering worst case, average case, and best case
- Affect the board
I don't know what single cards will signal these principles to your players. Making games about bombs and removal by making their power level high is a way to do so, for example, but I don't personally like it. I prefer to create an environment that challenges these limited basics, though it does have the drawback of not preparing players to play retail limited.
Edit: forgot to finish this part.
Awareness is everything
Most of all, I believe the designer having awareness of the cube's environment is the hardest part to get right, rather than identifying the didactic cards. Traps are quite damaging to an environment, whether those traps are individual cards or unsupported archetypes. At the same time, draft environments are so chaotic, jagged, dependent on human behavior, individual preferences, context, and variance, that it is incredibly hard to simply know what is good in the environment you created yourself, while at the same time maintaining the tensions and make it deep.
3x cycles of fetchlands and 3x dual lands (in addition to a few more cycles). For what it's worth, I have really enjoyed being able to cast my spells on curve, and haven't ever experienced the "color is arbitrary" thing* mostly because a) it's still Limited and you still have to make tradeoffs for consistency's sake, and b) the proactive decks like Zoo and Prowess are great at punishing mana stumbles which gives a very good reason to only splash responsibly. But again, fun is subjective, so I'm not trying to convince you or anything.
