Mob stacking definitely helps the server perform better and I agree that it should exist. But this plugins surely has some unwanted features as well. Mob stacking causes farms such as endermen farm , guardian farm and almost all the spawner based farm to be very less efficient as those farms depends on the sweeping edge of the sword. And this also ruins the purpose spawning of iron golems in villages as they will stack. So my suggestion is to limit the maximum no. of mobs that can be stacked(maybe 20 or something). 1.14.2 server doesn't have lots of spawner at the same spot so the spawner based farm shouldn't produce lots of mobs that could cause lag. Or disabling mob stacking when there is less player or only one player on the server would also work. I have also noticed that mobs spawns are very less in amount and there are almost no spawns on top of nether. 1.14.2 had a bug that caused lots of mobs to spawn at the same place. Hoping I'd get a reply from the mods or admin.