Based off Call the Gatewatch. What do you think?

What about a Moonmist variant to flip Radiants, with an extra effect to justify rarity?

Would that really be useful, since most Radiants will be at least rare or mythic?

How about for "You gain 2 life for each creature you control, then until end of turn, creatures you control gain vigilance and get +X/+X, where X is the number of enchantments you control."

Gaining life: Life before death.

+X/+X: Strength before weakness.

Vigilance: Journey before destination.

Out of curiosity, what part of its current design isn't working? Is it too specific?

I like your idea, but I would rather have it directly tied to the Radiant cards. Your suggestion got me thinking: Move it down to uncommon, and have it transform target permanent?

First of all, I'm not sure if "a card that transforms into a Surgebinder" is recognized by rules so I don't know if that even works. Second, yes, it's too specific. CtG searches for a well-established type, one with 74 unique cards. As of the end of this block, there will be 9 surgebinders, so a card to fetch them will be far worse than CtG, which is a bulk rare to begin with. Maybe tie it to investiture counters?

Yeah...Maybe, we can have the Surgebinders' transformation trigger once they reach a certain number of investiture counters. This card could be a choose one kind of spell, choose between investiture, life gain, vigilance, etc.

How about this?

I like this new version, should it be part of a cycle? You should probably define X in the last ability... ;)

Oops. It would appear I pulled a Roborosewater. :p

Sure. This would make a pretty good cycle, I think.

I wonder what roborosewater would do when prompted with Surgebinder, Stormfather, Spren, or Parshendi.

my only concern: right now your actual radiants are nonwhite, so someone playing a red deck and using Kaladin, say, wouldn't be able to use this, which is weird for a card based on the one universal radiant oath

Well, not many ways to solve it. Kaladin requires either Boros or Izzet, preferable Jeskai. The rest of the radiants are all over the place. Maybe we could make it WUBRG?

No, then nobody could practically use it barring a manbase like Khans-Battle standard with fetches and battlelands, which is not what we want. White seems fine, as Shallan, Szeth, and Dalinar will be white and Kaladin rewards you for playing white. Also, is the main enchantments matter color pair.

Yeah, the flavor of the oath itself is very White.

Balance Notes: Controlling even one enchantment, the last mode is decent in limited, and it's quite efficient if you've got two. The first mode is really good with Radiants flavorfully, but will be more useful in or decks playing a few cards that care about counters. The middle mode is less powerful, but as an extra option it's fine.