...Assuming this is actually a good fit for Gnome, I'm not sure where to
start either. Any indications would be welcome.It looks to me like Paperwork probably has a specific set of use cases involved - particularly someone who scans lots of text documents. Concentrating on that use case seems like a perfectly good goal to me.
I'm not 100% confident where GNOME's strategy is long-term in this area and would be happy to discuss it with you (just call into #gnome-design whenever you want). One thing that having a standalone scanning utility (in the shape of Simple Scan) does give us is the ability to scan different types of documents, that might end up in different places. Likewise, while we may want to look at Documents' role in the future, it does fit well into the triumvirate of Documents/Photos/Music. :)