A Troll raide? How about Zul'Forum! JK.
I would like to see WotA, would love to see Nelfarion's breaking point, (Broxiger on Dragon back), Alexstraza, Malfurion and Illidan in their day. It would make for a huge Plot reminder for anyone who did Hyjal questing zone and had no idea what was going on. It would have Zin'Azshari, one of the most magnificent cities in Warcraft lore, which we probably wouldnt see until a sea related expansion.
I'm hoping for more than just 3 Tiers. I love their raid design now as well. Like 4 bosses and a 5th unlocked if you've done hardmodes? And with each tier has about 3 raids, if remember correctly that's information from a blue post. So the raid content will be quite diverse nonetheless.