I don't think there's anything wrong witha build step as long as a) it's simple and b) there are distinct advantages. Most of the js ecosystem fails miserably

I don't think there's anything wrong witha build step as long as a) it's simple and b) there are distinct advantages. Most of the js ecosystem fails miserably at a). And for b) the advantages of es6 and / or jsx aren't universally appreciated. A good example of a build that IMO delivers both a) and b) is Elm. The build is simple (like compiling anything, but you can get all webpack complicated if you really want) and the syntax, static typing, and compile time errors add enormous value.