I think there should be a self hosted WIKI that is included as a part of Home Assistant. When you gain access to the portal, there will be a help section. From here you will be able to author detailed documents about your home’s setup. There could also be some standandard troubleshooting tips included (that you can edit) This would be something you could share with contractors, or future owners in the event of selling your home. You could also upload and save PDFs of all the different hardware that make up your system. At this point if I sold my home, there is no way I could keep home assistant running for the future owners. A place to document all the intricacies of your individual setup would make that a little more possible.
Being able to upload a picture of your homes layout would also be a cool feature. As you add physical devices, like sensors / lights and locks… You could drag and drop icons that represent the devices on your network. When you have a device that needs batteries or happens to be offline, it would show on the map. It would also be nice to see a general idea of your zwave mesh network coverage (this would mean you need a drawing to scale). This same online wiki should be exportable to PDF to either store on a thumb drive / CD / or Print for offline use.
It would be ideal if my wife could diagnose home assistant not working. Even if that were as simple as unplugging the server and plugging it back in. I realize that its up to me to document, but having that documentation update and talk within home assistant could be a really nice feature.