I disagree. ES6 made JS much more palatable but it's still behind most modern languages in terms of number of features
and in velocity of new features getting introduced. Javascript has actually been extremely slow to get new features compared to other languages.
Since ES6 (3 years ago), the only major, mainstream feature that has been added to JS has been async functions, which are awesome, but in that time Python (a language of similar age and global use) has gotten an optional type system, async/await, and _hundreds_ of standard library modules, classes, and functions.
In my opinion, JS badly needs more functions in it's standard library, which should move through the proposal policy quickly. However, common sense standard library functions like flatMap have been in the pipeline for years are still not in the final stage. We may not get flatMap, import(), trimStart, or trimEnd in ES2019, they are all stalled in Stage 3. There's no good arguments not to have these in the standard library, but we still have to wait years.
In addition to that, JS could really use some language features that make it's core paradigms, functional and object oriented, simpler, and have been in other languages for years. The pipeline operator would make functional programming much easier, and decorators would make object oriented programming easier. These are, in my opinion, common sense features since they are so well received in other langauges, but they get stalled out since they are seen as "bloating" the syntax, or making javascript "too opinionated on how to do something". Meanwhile, people are compiling full fledged functional languages (Reason, Elm, Purescript) to Javascript, because Javascript isn't keeping up with them on features. It could, but the TC39 review process is so slow that it's not worth waiting on. For those reasons, in my opinion, we should really be releasing new language features much quicker.