Here are my top three things that I would LOVE to see implemented.
1. The Naylar homelands of Hadar, Sendras and The Gana-Isha: I love the Naga (or as they are now know, The Naylar) and want to see their homeland added into MassiveCraft in more then just lore. It would be very interesting about how such a place would be handled. would it be a quest island, would certain areas be protected or would it just be like most of the other survival worlds? Sendras is the home of the Slither and I have no idea where it is although I assume it is somewhere close to Hadar. Then there is the Gana-Isha/The Rift. The Rift hasn't really been explained in the lore and I think having it back would be very useful in terms of the beginning of logical Dakkar factions.
2. More Districts in Regalia: Yes there is the Poor District, the Common District and then the Imperial Palace but what about some more? I remember when there was the Non-humans district, where the Maiar Embassy was located and many small yet colourful houses took up a part of Regalia, but that was deleted when the Park District was added. It would be great to have someplace like that back or, for example, have a Guild District where there would several fine and larger then normal buildings that could only be rented by guilds for their homebase. Another would be an Imperial District, which would include Noble Housing, The Imperial Palace and then some more Imperial buildings of governance like an Imperial Trade Bureau or an Imperial Information Centre. (Bad examples but I'm sure our lovely staff can come up with some more creative names or ideas)
3. Turn the Old Spawn Building into something useful: It is apparently a "Klienfolk Registry Office" right now and I have no idea how many forms it receives for applications of "citizenship" or whatever yet it is remanent of the server's past and I find that it isn't really useful in doing anything right now.