I obviously can't speak for the whole community, but it seems like a lot of people are not happy with .mjs.

One of the main arguments to keep .js is that if we can detect 99% of cases where we CAN tell if is it CJS or ESM (or where we just know what to do), we may just call rest 1% edge cases and deal with it.

We can even come up with some linter rules and/or workarounds to simply teach people to do the right thing.