This is exactly what we do, and suffer zero issues. You have the globals (color scheme, typographical rules), and then you have the component-based, scoped SASS

This is exactly what we do, and suffer zero issues. You have the globals (color scheme, typographical rules), and then you have the component-based, scoped SASS. I don't see any reason to do it any other way, and it scales just fine for the systems we build.