I needed to ask about this division because I'm rather new in this community, and I created the tool which is devoted to simplify development of UI (react-ui-builder). And now I'm deciding if I need to switch generation of the source code to ES6, or wait a bit.
You can still target ES6 and have people use a transpiler to hit ES5, noting that not everybody is familiar with the tool chain(s) necessary to do that efficiently.
