Greg, that's fine by me.
WRT the ComponentNode use-case you mentioned, that sounds potentially very useful, but it brings some interesting problems
It means that the Document model is no longer share-able between multiple TextArea instances, because the Component will need to get inserted into the TextArea's containment hierarchy.
I don't see it as a real problem, it's just something that will need to get noted in the docs and checked for (with nice exceptions) in the code.
Keyboard/mouse/focus interaction is going to be "interesting" with editable documents and live components, and will likely lead to some surprising results when people stick Components into their documents.
I'm inclined to say that we should enforce that we only support live components in documents in non-editable TextArea's.