Hoarder: Drops a guaranteed i.lvl 63 item
Rich: Drops 10x the amount of gold
Ancient: Increased chance to drop a legendary
Appraiser: Drops a guaranteed 6 affix item
Cursed: Gives the player a very nice damage buff upon defeat.
Traitor: Shows the player the location of the nearest Treasure Goblin upon defeat.
Jay Wilson: Fixes this game upon defeat. [joke]
just stuff like that can make a game go from being terrible to really good. Not every pack would have these affixes and they wouldn't take the place of one of the four players have to overcome, but it might make a player want to fight that Shielded, Vortex, Molten, Extra Fast elite pack of killer spiders.