This is sort of what Nate Kontny is doing with Draft, which I like kind of a lot, much more than I expected to.
My feeling would be that having one platform with both features would be better than having two very similar things here.
I much prefer a system that's geared to projects and not specific types of document too. For example, if this supported housing a collection of documents and an image or two - with changes able to be made on each file, it would be amazing. Google Docs I edit with others quickly tends to devolve into three different types of sharing/permissions issues, and I'm left frustrated or wondering why some people can access one thing or another.
There's definitely room to innovate here.
Nailed it. That's what I'm building :)