Here's an interesting article contrasting the development paths of the two types of MMOs, themepark and sandbox:
It seems relevant because I have a feeling that most if not all of the people keeping an eye on Xsyon are interested in systems over content.
Also, it should be encouraging to realize that EVE Online probably started out with roots similar to what we're seeing with Xsyon right now. And look how successful EVE is now.
Hell, it even gives hope to Mortal Online.