What the title says, I believe that once we have enough trusted players we could make this a public server and make an actual nation instead of a few people on at a time.
Then again, it would also promote griefing, and would require several things to make the server mostly safe:
1) Backups: NEVER delete an old backup in case something happens and we didn't notice a griefer in an earlier update.
2) Moderators: We would need at the very least 1 Moderator for every time zone, including asian and etc. time zones. This is why we should stick with private atm.
3) Dedicated Server?: Because of the influx of people, we would possibly have to get a dedicated server running 24/7. This could be done if someone feels generous our buying the server and asking for donations as people come and play.
4) Rules: We would have to make sure people would see and follow the rules, such as no griefing, no pillaring unless building something, and etc. We would need a way to make sure every person sees and abides by these rules.