People really need to stop lumping Zul'Aman and Zul'Gurub together. Zul'Aman was the poor kind of rehash - it's almost exactly the same dungeon, but updated for max level. Even though the final boss is "new," he has essentially the same mechanics as Zul'jin did. Zul'Gurub was the good kind of rehash - same terrain, completely different experience. Even the bosses that returned from the original version are almost nothing like the their level 60 incarnations.