On the modded server I frequen they use a space station to welcome new players. Unfortunately they have to use bubble generators at the spawn point instead of sealing it and filling it with oxygen because the invisible oxygen blocks cause issues with spawning there. Those blocks cause other problems too, for example they had trouble using Lanteacraft's stargates because of them.
I propose that the world have regular, breathable, ID-0 air blocks but, unless there's bubble generators or oxygen sealers to remove them, any place that would normally have ID-0 air blocks would be filled with invisible vacuum blocks which would have the same oxygen deprivation effect as being exposed to the current ID-0 atmosphere.
To facilitate upgrading a world to the new system you could add (unless it's already there) a version number to the galacticraft dimensions and anything created by the previous version would have the ID-0 air blocks replaced with the new vacuum blocks, and any galacticraft oxygen blocks replaced with ID-0 air blocks. Alternatively you could have a config option to choose between the current oxygen block method and the new vacuum block method as well as a single-use "vacuumUpgrade=true" option to instantiate this process.
I propose that the world have regular, breathable, ID-0 air blocks but, unless there's bubble generators or oxygen sealers to remove them, any place that would normally have ID-0 air blocks would be filled with invisible vacuum blocks which would have the same oxygen deprivation effect as being exposed to the current ID-0 atmosphere.
To facilitate upgrading a world to the new system you could add (unless it's already there) a version number to the galacticraft dimensions and anything created by the previous version would have the ID-0 air blocks replaced with the new vacuum blocks, and any galacticraft oxygen blocks replaced with ID-0 air blocks. Alternatively you could have a config option to choose between the current oxygen block method and the new vacuum block method as well as a single-use "vacuumUpgrade=true" option to instantiate this process.