There is no real need for this for standard claims as claimblock cost would be complex. A 3D subclaim could be visualised by showing every edge. A simplified version would be for people to have access to a specific chest or to place in a specific single block. Spawn has this at community farms so it may be possible to implement this for normal players? I don't know how it works so it could be that it isn't possible.
A suggestion I would like to put forward is for players to have the ability to create subclaims in 3D. Instead of selecting the two opposite corners and the sub claim reaching from bedrock to build limit, a player can choose to select the top corner and bottom opposing corner similarly to when copying and pasting with world edit and then trusts will only apply within that area and at that specific height. This could allow for people to make hotels or skyscrapers where they can trust people to only their room without them being able to tamper with other people's. This would probably be encorporated separately to the normal sub claiming and enabled using a different command such as /advancedaubclaim so that people can easily assign normal sub claims too.
It probably doesn't come as news to you that Aero Survival is home to multiple large groups, each with Allies, Enemies and Fugitives. The Global Empire is one of the largest in the server making up over 20% of the Server's overall wealth. It makes vast contributions to the community of the server including running the largest mall and some of the most played Player-ran minigames serverwide. It therefore is clear the importance the empire has in the success of the server.
Players in the empire have prospured massively since their joining. This is partially because we are open to the joining of any players including new players who are yet to earn their riches, others have benefitted from the free and useful services the empire offers. An example of this is the free farms available to players who join the empire. Bamboo, sugarcane and bulk smelting utilities are usable by all players who join the empire. Job opportunities are easy to come by for citizens of our great nation including miners, builders, technicians and managers. Our economical subsidies and wealth management program ensures all players earn well. We offer free prime real estate at Mushroom Warp for players to build shops without the requirement to pay a tax to the empire. Instead we use our own currency to ensure players always have an equal opportunity when it comes to building shops and homes.
Another major benefit of the empire is our participation in PVP and other events. The Global Empire is in part managed by one of the most successful players in combat: MercyInnit. He has won over 90% of battles he has participated in and definitely isn't spying on the Ender Sages for us. We also have other PVP experienced players in our group. We have also had major victories in battles due to our superior weaponry. We invest heavily in our defense program, stationing ICBMs serverwide in case of security emergency.
I'm sure you can realise the major benefits of joining the Global Empire. If you would like to Enrol please message RedstoneBurnout or the Minister for Employment, MercyInnit.
I have been an advocate for the implementation of a blanket no swearing or inappropriate language rule. It would both increase the player base (as it allows parents to let their children play) and just make others more comfortable. I think a step in the right direction would making death messages child appropriate. I'm not talking about removing violence from it but the ones for players killing each other involve swearing which could be removed.