Also the mystery of Zul'Gurub gets brought up in no less than 4 zones (STV, Feralas, Tanaris, and Hinterlands), then you find out Hakkar's return will happen there one day. Then bam they release the ZG patch and it all comes full circle. Its so cool and well done for Vanilla.
-
Yes you basically go about learning more about all the old bosses and it gives a lot of new lore to the old raid characters. Turns Jin'do from a joke from the original into a real threat.
Especially when you realize Chronicles had Vol'jin be the one to technically answer the phone that King Rastakhan called the Horde up on. And then Vol'jin helps Talanji out with dealing with him once again - have this be a once and for all sort of deal.