> async/await, classes, arrow functions, etc. However, despite the fact that all modern browsers can run ES2015+ code and natively support the features I just mentioned
What is everyone's cutoff for de-supporting a browser? According to caniuse.com[1], >30% of browsers don't support the mentioned feature-set; that seems like … a lot.
(<script type="module"> is listed at 60% unsupported, which seems very high, but his point that if you allow it, you should allow everything else mentioned seems sound. I also heavily agree w/ his point about delivering modern JS, and letting end consumers transpile as needed.)