I know that in Skyblock it isn't allowed to make splash potions as you could hurt other players with poison potions, weakness, etc. For the newer players who can't afford villager spawners, Villager Zombies are the only way they can get them. Is there another reason they aren't added other than harming other players? Is there a way to turn it to "Hey! You can't pvp here." when a potion is thrown at a player out of warzone? Just a thought! :)