Great questions!
>Which of the current JS frontend framework paradigms do you think should be standardised and shipped in browsers?
The basic concept of "binding" data to a DOM element and having the DOM element update when you update the data instead of having to manually update it. That's something every modern frontend framework does.
I think under the hood, the people who actually write the DOM apis would know how to do that in the most performant way possible. I know any native approach would certainly be faster than a Javascript framework. To me the more important part is getting the API surface right.
That's the big problem with a lot of these standards updates. They kind of half assedly add a feature that's inconvenient and then nobody uses it. They need to think more like "How can we incentivize people to drop X framework and do it natively?"
>if your proposed solution would look similar to current JS solution X, why would it be better than X?
It'd almost certainly be faster being built into the native code, but yes the goal is to remove the build process and tooling. But also to bring things back into balance. Right now, most web apps are a big bundle of JavaScript. But with these changes, it'd be several HTML files, JS files, CSS files. In balance again. Each technology has its own place. I think the average skillset of front-end developers would improve massively if they didn't have to do stuff like chase down NPM problems or debug Webpack.