I see here one issue - managing a website in 3 places soon, backend-settings, front-end editor and something between both - Customizer. Not any of them are fully capable, every part do something extra or just duplicate an existing function.

Customizer + fully capable front-end editor would be great, if backend will disappear completely.

What I don't like on any website or system, is too many clicks (or anything) and Customizer is a click farm where are always some new clicks available.

Regarding "hot and loved" topic telemetry, I turn off anything I can on any machine I use. Testers should test, users should use.