Perhaps I could find a way to transform
    imports into script statements in the exported file

Uhh no! That would be even more hidden magic. The beauty of your platform really shines when there is no hidden process. When the user can transparently see what happens.

There really is no difference between Vue and React in this regard. The React demo without a server side toolchain looks like this:

https://frontarm.com/demoboard/?id=2e5ca405-b011-4d00-988d-2...