I suggest you get over the old document concept and focus on information. Confluence allows you to manage information. I say that information is liquid, and can take many forms, like water, depending on the container. While a document inside sharepoint (which I know just as well and as before Confluence and sharepoint I knew lotus domino very well) is a container that stiffens the content. The information is folded to the container. Take a step forward and go beyond the old concept of the "word" or "pdf" document. Today information is liquid: web pages, chat, sms, even videos don't you think ?
Confluence works way beyond your old and tired ideas of Sharepoint (where documents go to die), Slow Toss Notes and the rest. It is, at heart, still a wiki
It's content is as liquid as you suggest it should be, in my experience. I suggest that you get over the old document concept, focus on information and adopt the use of wikis such as Confluence.