I guess that brings up the question of, is there any word processor for the Amiga Classics that support ODF?
Probably not. The ODF format is just XML (from what I've read). Would be really easy to handle, but it's probably just not supported.
it'd be fantastic if even our beloved Classic Amigas could be used for modern day writing / word processing.
You can. You can use your Amiga to write anything you want :p As far as program compatibility goes, try to find a format that's supported by Open Office and Amiga software. Of course, you probably did that already, right?