[gorgoiler]

You present two choices:

1/ no compilation step during development, but it breaks old browsers;

2/ continuous compilation while developing so that you support old browsers;

…but there ought to be a third option that would satisfy everyone:

3/ no compilation while developing, and one compile step at release time to support older browsers.

[xena]

Ironically this is the kind of thing that ES6 modules actually solves. It's even better if your tool is internal-facing only so that you don't have to bother with the release time older browser compatibility thing.

[tompazourek]

ES6 modules are just brilliant, it's like a breath of fresh air in JavaScript development. Your browser sees exactly the same thing as you write, which is such a great simplification. And yeah, you can still bundle/minify for production...