In Vanilla WoW there were the 8p Dungeon sets that could be further upgraded
Burning Crusade you had your two types of Dungeon sets EX: Warriors had Bold for tanking, and Doomplate for DPS (Not limited only to warriors, <3utopallys)
Honestly I considered the Dungeon sets in WotLK to be our T7 10/25 man gear. There weren't any actual sets to gear up for from 5 mans, and the Tier 7 was just a remake of Tier 3 while also being extraordinarily easy to get.
Cataclysm? Would you like to see actual Dungeon sets come back? Or keep it the way it is now.