To be honest, FFXIV is probably the only game that makes me want to be more social. Why? Because I can do either my own thing and not be bothered, or be with other people and do something. Private servers would also mean it's harder to get things for crafting. In order to multicraft, you'll have to actively level gatherer, be a multicrafter, and know where to find everything.
The only way I can see private servers working would be for RP, but even then, you'd have to unlocked most things and be at least lvl 70 to not get eaten by overworld creatures.