Another example could be a jelly plate or a protruding belly with it's belly button, a tongue clear coated to look slimy, a snail with a rigid shell but a soft body. Anything wobbly.
I'm dead serious about it and I'm gonna do it anyway. I was curious about the public interest in something like it and still need some feedback. Maybe when I have a prototype and some testers if everything goes according to plan. It means a whole lot of different possibilities for keycaps.
I don't want to vary only the colors of the caps, that's boring, there are a bunch of materials to experiment with, (nitinol wires for some heat activated thing, maybe a folded origami inside the body of a keycap made in acrylic, that deploys with heat changes: if the metal is thin enough, the heat of the fingertips is enough to make changes, etc...)
I'm discussing it strictly using descriptive terms, personal appreciations aside, but feel free to express yourselves.
Why not do it now? there isn't a single reason not to. The medium is mature enough.