At this moment the API only allows Overworld, Nether and the End as Dimensiontypes.
Dimensiontypes define some settings around fixed Worldtime, hasSkylight, isUltrawarm, isNatural, isCreateDragonBattle, isRespawnAnchorWork, minY and also the height of the World.... and also which Blocks can burn infinity and which not.

My idea is too add a Method to the WorldCreator that gets a Object called 'DimensionSettings' that contains all those features, by default Overworld-Settings are loaded and with just 1 Method other vanilla-Settings can be loaded. 

All it would need to work is some changes in CraftServer where the "createWorld" Method runs.