It is good to make this public.... we ran into this exact issue with Microsoft's XNA content pipeline before.

We really want MonoGame's content pipeline to be flexible and allow users to embed it into their own tools.  This means making some key APIs public instead of internal like MS's implementation.  In this case people could call content importers and processors directly, but could never call the content write/compile directly.

That doesn't mean we make everything public...  just what is useful.