It would be great to be able to change how far a mob is spawned locally rather than globally.
Ive been trying to balance Illager+ mobs with Ice and Fire Dragons. The dragons won't take flight reliably unless they are spawned at least 150 blocks away, but the Illagers seem to despawn if they are spawned that far away. Being able to tell one set of spawn entities to spawn at one distance, and a different set of spawn entities to spawn at a different distance would solve conflicts like this and provide more options for modpacks.