What I Want from My Writing Tools

I’d love to write in a tool with all of the following features:

1. Helps plan writing in the unstructured ideation phase and surfaces connections in existing writing
2. Uses Markdown natively with full support for images and tables
3. Supports both cloud sync and saving to the file system
4. Beautiful and supports theming
5. Lets you publish anywhere in a single click using custom export hooks
6. Supports tags
7. Lets you share drafts and get feedback from friends
8. Is web-native

The last one is more of a matter of taste, but I strongly prefer writing on the web as opposed to in a desktop app. When it already feels like my writing is in the ether, it takes less cognitive effort to publish.