They dropped EcmaScript Edition 4 because of internal fights between Adobe and Microsoft - and I doubt they have resolved their issues as it's a clash of mega corporations. Right now, most of the proposed changes in EcmsScript Edition 5 are minor and there will go a long time before they are used by the mainstream developer. I think most future web development will be focused on HTML 5, CSS3 and improved performance of JavaScript - - which is a shame, since EcmaScript Edition 4 implemented correctly would have made a real revolution.
The first update to JavaScript in nearly a decade and rather being happy that the revision introduces some nice new features, fixes some of the biggest problems with the standard, and has been embraced by all parties so should have a relatively quick introduction, people would rather moan that it's not enough.
