But I think that
> html in the middle of your code
is selling JSX a bit short. Tooling and coupling aside (and I agree those are strikes against it), JSX creates a pair of mutually-recursive, formally-defined languages, which you can switch between freely and frictionlessly. I've never seen this before, not even in lisp, where quoting/unquoting is bad enough at a single level.
This—the ability to compose languages—is extremely powerful in general. Even if you don't like JSX per se, I'd bet there is some set of languages that you'd like to be able to use this way. I'd look at the "controversy" around JSX (and Babel and the React dependency) in this light, as a learning experience.
For example, JSX is really just a variation on EX4, which has been around for much longer. A number of "external" factors have put JSX over the edge (of mass adoption), and these mostly have to do with React's popularity. By the time I capitulated and decided to try React, I found that I already had tooling support for JSX, even though I was pegged to Babel 5.8 for reasons.
I think this is the principle behind OMeta: we should be able to iterate on language features as freely as we do on application features. We ship applications, why shouldn't we ship the languages, too? (Of course OMeta came out of VPRI, and Alan Kay's view is that we could just ship the whole dang system!) Anyway, from that perspective, JSX is no more "insanity" than some of the things we do to work around the rigidity of languages-as-silos.