Its a tangential example to be sure, but it seems to have worked out really really well for Google Chrome and their extensions.

I haven't been this excited about a windows release in a long long while ... I hope Microsoft doesn't botch this

I wouldn't say it's a tangential example as much as that Chrome extensions have a very good reason to be written in JavaScript--they're effectively contributions to the JavaScript of the page, and use the same DOM.

It remains to be seen if the other benefits of JavaScript carry over to Windows 8 enough that it's worth using it to code desktop apps. As for botching it, I suspect that Windows 8 will be a not-very-good «experimental» thing like Vista and Windows 9 will be what Windows 8 should have been in the first place.