Without plugins at first, how open are you to contributions that would normally go into a plugin and not into core?

As someone who works on libraries that don't use JSX, and therefore have to rely on compiler and linter plugins to get support (tagged template literals in my case) I worry that React's dominance will mean that it gets a place in Rome, while other systems are locked out, which only increases React's dominance.

Would you consider an internal plugin system as a first step, where plugins have to be part of the codebase, but intentionally get a restricted API surface? This would allow you to try out and refactor the plugin API over time before committing to it publicly.