Yeah loot was random, but it spawned with that random loot. They jus changed what mobs can have in their loot tables which isn't a hard change, but actual loot that wasn't spawned with the mob is a hard change. And doubt they could even do that. Edit: now they could add a quest you could grab that pertains to world bosses you could have. N if you complete the quest( do x dmg on world boss) it could reward you.