"Fewer than four colors" feels arbitrary and wonky. Even in this (or any) environment I have a hard time seeing it ever being that relevant of a restriction.

Noted:

My idea was a "Four mana spell that destroys a creature with four + power unless it has four or more colours." , under the idea that using 4 repeatedly was more elegant.

And this is supposed to be "Four Colour Matters" set where players build decks to play four colour creatures is limited, so I am trying to make an environment where that restriction matters. (That's also why I'm trying to make Gold tokens a major mechanic.)

I will consider cutting this card.

And thanks for the feedback.

Suure.

Also worth of note might be that having multiple not-so-simple-restrictions can have the Dead Ringers effect where it takes time to parse what the card actually does and the card comes off as extremely inelegant.

Understood.

I have changed it from "has fewer than that four colours" to "that isn't four or more colours".

Does this make the card more intuitive/elegant?