Red seems to be able to do things outside of its color so long as there's an alternative option for a player to take damage. Risk Factor and Combustible Gearhulk offer card draw, Vexing Devil provides a creature way out of bounds for its cost, and even Enchanters' Bane allows for red enchantment removal which is normally a notable break for the color. But they all work because they offer the option of damage as an alternative. Could other colors receive something similar for their own effects?

Red has the right combination of a theme of chaos and the #1 color for direct damage. I don’t think there are clean answers for the other colors that will feel in color.

This may fall outside the bounds of questions you're allowed or inclined to answer here, but with what intent did you design Vexing Devil? Was it intended for tournament play, teaching new players lessons about trap cards, or just as an experiment? Or something else? I've been wondering about it since the card was first spoiled, and I haven't seen you, Aaron, Zach, or anyone else address it yet.

Design tends to make cards hoping to make cards as fun as possible either because the card in isolation is interesting or the card fits the environment well. Development figures out which cards they think best work within the environment that the players will enjoy and push those.