On my realm even when there is just one player on it the TPS(ticks per second) drops below the normal 20. Then when 4+ people join it drops to almost half or a third. The world is still playable, but flying with elytra is impossible. Once the realm fills to its max of 10 players, I would classify the TPS as unplayable as it probably dips below 5. This was not at all how it was before and only started happening when this change was introduced. Also I am not 100% sure but I have built multiple farms that rely on sim distance 4, and if the mob spawning radius changed I would have to rebuild the farm.
On my realm even when there is just one player on it the TPS(ticks per second) drops below the normal 20. Then when 4+ people join it drops to almost half or a third. The world is still playable, but flying with elytra is impossible. Once the realm fills to its max of 10 players, I would classify the TPS as unplayable as it probably dips below 5. This was not at all how it was before and only started happening when this change was introduced. Also I am not 100% sure but I have built multiple farms that rely on sim distance 4, and if the mob spawning radius changed I would have to rebuild the farm.