Dropbox Paper shows us a glimpse of the future. However, if it wants to become a real killer, it should allow more flexibility for outlining information (it does exist within documents, but not among them!).
What about becoming more wiki-style, like some past programs (SeoNote, Treepad) or present services such as Confluence and Notion.so? Why not allowing people to organize hierarchical structures according to their needs, instead of storing "papers" in "folders"? (come on, it's 2017!).
Please take a look at Notion.so and all will make sense.
I think this is the future of information management. I really want Dropbox to embrace it.