Thanks for the feedback, it’s very much appreciated — keep it coming!
Comments on specific points below. Follow-up questions in another post.
We haven’t gotten there yet, but that’s the plan, yes.
Grid is not part of the scope for this feature.
We’re definitely looking to add support for this new layout mode to the web app, with properties in the inspector, and flexbox code in the CSS output. But we don’t have specific plans to add other languages/frameworks at this point.