Respectfully, you're failing to engage with the purpose of the project.
> it's not an alternative to the web
Right. You can't have a lightweight drop-in alternative to the web, pretty much by definition. Any platform capable of everything modern browsers are capable of, is by definition enormously complex.
> it is a very very small subset
That's not a flaw, it's a design goal. It isn't meant to be a half-baked portable GUI toolkit the way the modern web platform is, it's meant to be a simple and minimal format, stable and easy to implement. There are other formats somewhat like this in common usage, like man pages and, of course markdown.
