You might find this interview with Continuum Creator Lippold Haken to be of interest. Haken is the creator of the Continuum Fingerboard, an alternative keyboard controller. Lots of interesting thoughts about creating expressive musical interfaces. You might find some interesting analogies to expressive programming language design as well…​

I go to the NAMM Show, and almost every piece of software, almost every instrument claims that you’ll do great new things with it, and there’s no learning curve. I didn’t take that route. That’s not important to me.

It’s not good as an engineer to make something needlessly difficult, but it’s also not necessary to de-skill musicians. I mean, I don’t want to make another instrument where the main purpose is to replace acoustic musicians with a single person who doesn’t have to learn.

Recommended to me by Rich Hickey…​ :)