Create great raid bosses with a map filled with a lot of bosses for 4 players with new end game reward

Example:

Shark teeth pendant to equip on ear - with 4 random affixes. (so you can make a lot of stuff like a horn to tigh on belt etc).
Bear Cape - with 4 random affixes, (so you can drop a lot of diffent fur animals capes).

These stuff just could be dropped after reaching endgame. So it would give a lot more things to pursue.