This might be a long shot, and maybe not useful in most cases, but I think it could come in handy on both privacy and tinkering fronts. I know we can install from one phone to another using the web app, which is great, but the two problems with that is the image has to be downloaded each time, and you have to constantly keep reconnecting the devices via browser (whereas PC goes from start to finish).
It would be great to have a simple app that could do this locally offline with a cached version, and automatically update said cache each time a new release comes out. The connection issue isn't as major, but for those who might be doing it on a slower connection, caching and using another device instead of a laptop could be very useful. Not sure if anyone would see them doing this much, but I'd imagine the app built for this would require little maintenance (similar to the app store).