In reply to Henner.

Hey Henner, a couple of points in regard to your last remark:

The compiler Blocksy uses (which is just webpack and sass wrapped in a common package) is not private at all, in fact you can get theme's code, change the JavaScript files and run the build process yourself to see the changes applied in the theme.
While the options are implemented with React (and JSX), they are configured with PHP. All of the options live in inc/options/* folder of the theme, if you care enough to take a look. And there's nothing minified/compiled there. Of course we won't suggest to edit them yourself. I'm just pointing out that nothing's obscured.
While the Customizer may look like it has too many options at first, in reality everything's really tought out very slowly and carefully. Every option is located exactly where it needs to be, with respect to the site elements hierarchy. Happy to hear back from you what you've considered to be redundant from the Customizer, to be able to have a productive discussion.