I never jumped on the CoffeeScript bandwagon .. I know people love it, just not me. Hence unlikely I will try TypeScript.

Despite all its glaring flaws, javascript is an insanely productive language due to excellent mix of features. To improve upon that Id need to go to lisp / clojure [ but it lacks wide commercial acceptance .. not a criticism at all ]

I'm actually wary of using the newer additions to javascript language - ES6, Promises and arrow notation don't seem that much of a win to me, I'm very sceptical of new being good in language design...

whereas I really love Ramda.js as a general underscore / lodash replacement.

Productivity seems more a function of how we structure our code [ eg. keep state so we can jump back into where we were in the web app, thus iterate easily - as per the Om approach ] and thinking functionally.. rather than language syntax additions.

I don't see the need for an IDE .. they tend to come into their own when Your.ColourfulAndCompleteMethodNames are so long they need auto-completion. Thats the beauty of javascript [ and lisp etc ] we should fight to keep things small and terse.

I don't want to argue on your other points but imo the part of auto-complete that saves typing time is the least important thing in a IDE. The really useful part of auto-completion is actually exploring unfamiliar APIs.

no! :) static errors analyzing is more important - saves much, much more time.

Of course that's he best part of the IDE, i was only commenting the autocompleting part.

Es6 has destructuring and tail calls, too.

I also like cljs, mostly in a text editor.

Code quality it is the ultimate time saver. I prefer reading concise, literate source to exploring/churning APIs.