There are a few things with that. First, we focus on SQL Server, so we want to host on SQL Server.
Second, there are things we do that can be modeled as documents, but aggregating those together and working in groups is better handled relationally, IMHO. I think forum posts, which are linked and cross linked, are a better relational fit than a document. Questions and answers, likely better relationally.

For the articles, sure, those are better fits for documents, like DocumentDB, but since I also need to put things together later, that might not be easy.

However, at our data volume, this is a wash, and the request count is tough to calculate and decide what's better. Ultimately I think doing this on DocumentDB would work, but there would be a learning curve, perhaps a large one, and things might not be as smooth.

It's easy to napkin scratch how things might work. Much harder to actually make them work. Perhaps even harder to port them over and deal with the issues as you get things running.