I'd rather have Lua to be honest... But JS is better than AppleScript in this regard. While easy to understand, it wasn't suited for large projects and debugging was kinda nasty.
[0] http://lists.apple.com/archives/applescript-users/2014/Sep/m...
This is especially true when it's an environment where there are numerous other languages available, and they're all so much better than JavaScript. Lua, Python, Perl, Ruby and even Tcl would all be better choices.
It's mildly excusable when it comes to web browsers, because JavaScript really is the only viable option. But that just isn't the case with a full-featured environment like OS X.
Who appointed you paragon of objectivity? Myself, I think JavaScript is a very good programming language.