Sounds familiar. 
Welcome back. 
Would you use pie for this?
I’ve wanted plugins for a long time, so I’m in favor of exploring this. I love the idea of external executables instead of dynamic linking.
My only real concerns are around security. Regarding Footnote 1, I take you mean that you will provide a working plugin framework, but it’s up to someone else to deal with the concerns in #796. Am I reading you correctly?
How would we handle funcMap entry overloading?
My take: A full blown proposal may help avoid wasted effort. If you can define and implement a working plugin framework, I suspect we would figure out how to solve the security issues in #796.
PS - I’m also curious about a client-server framework where the plugin stays running while we pass it work to do instead of separate exec’s on each funcMap invocation. But I’d like to see how fast (or slow) your framework is before we spend time on a client-server framework.