It's funny, I had a different but quite related thought about a new take on a state register of land today.
We all worry about "tragedy of the commons". Imagine if a Blockchain Network (henceforth "The Network") could own property in itself. People could offer to sell property, previously registered in traditional ways or not registered at all, to the Network. The Network would collectively vote on the proposal in a similar way as we do now, in a negotiation process that would need to have some anti-cheating mechanisms just like Steem does today. They would then be available for sale, whenever a similar negotiation process comes to an agreement (it would last as long as it needs to last, perhaps indefinitely).
Over time this could develop into a general registry, of mostly land but it could contain other property as well as things that were formerly considered "commons". It would be a formalized market system of both collective and private ownership. Importantly, there would be no central authority. It's an open question whether or not The Network would dedicate resources to maintaining and securing it's property in practice.
I haven't properly thought this through, but I feel like it's the beginnings of something.