I read through most of J:TGP, but the problem is that it doesn't really focus on the DOM at all (which I knew when I picked it up). Unfortunately, the DOM is the entire reason I'd realistically want to use Javascript anyway.
Most 'popular' languages these days are descendants of C in some form, which means that the differences between any two are very small, in the grand scheme of things. (I'm talking about programming paradigms here - I understand that things like running time and library support are real factors, but to me those define the implementation of a language, not the language itself).
Javascript may be different from most C-derived languages in that it promotes certain paradigms that others don't, but to me, it doesn't offer anything as a language that other languages that I like (and use) don't. Prototypal inheritance is familiar to me from Python (yes, you read that right), and functional paradigms (including first-class/higher-order functions and closures) are familiar to me from Scala and Lisp.
If we want to talk about actual implementation and the runtime environment, I'm still not convinced that Javascript has any real inherent advantages over other languages for most of the non-DOM tasks that people try and use it for. Maybe it promotes familiarity with a single language, but I see that as a detractor, not an asset.
So in the end, while Javascript may be 'more than just the DOM' these days, for me, that's still where its use case lies. Just because I can use it for other things doesn't mean I want to; for anything that I want to do other than manipulating the DOM, I can find an environment that suits me much better.
