This is the workflow I've always dreamed of. In a lot of ways making a change which is then submitted as patch to their patch isn't really that different from submitting a comment to their patch. The workflow of doing that directly in editor is just wonderful.

If I had to pick, I actually think ONLY being able to submit "counter-patches" would be better than only being able to submit comments. Comments could just be actual programming language style comments submitted as code changes.