Hmmm. This is a very complicated mechanic.

To keep the same idea, what if you had "generic" Listener cards with "a deck can have any number of cards named ~" and "Reveal this from your hand: You may cast a Listener card you own from outside the game."

Or "Reveal this and a Listener card you own from outside the game: You may cast that card. Activate this only any time you could cast the card from your hand."

How about giving each Listener the ability Listenercycling ?

Yeah, it is super complicated. The only reason I'd even consider it in its current state is because I would be playing it with people who understand the rules well and could handle it. I'd love to make it better, though.

Your suggestions are good. I'll make a mockup and see which one works best.

EDIT: I think the cycling one works best. It accomplishes the goal of the mechanic while being relatively simpler. Typecycling is still complex, but not nearly so much as formshift is.

It seems like a very reasonable substitution.