[spion]

Okay, except for JSX I agree that the change towards native classes is for the better.

But the change in JSX seems to be just for Jest. JSX could still compile to function calls and stay completely decoupled from React. A new function `createFactory` would be introduced that takes a class argument and produces a factory, making ES6, CS and TS users pleased. No backward-compatibility breakage would be introduced.

edit: removed a non-constructive paragraph. Will play around with the new version more before commenting further. Hopefully I'll understand why JSX is a lot more complicated than it used to be :/