Thinking about the old class quests and how they were a “coming of age” metric of sorts. At 20 and then again at 50, you went out and took on the challenges put in front of you. The early ones were in dungeons, the latter, an epic questline (OK, some of them weren’t so epic). What if, Blizzard dedicated an entire zone to class quests and learning your class?
It could be really neat. Perhaps similar to Timeless Isle. I would make it a level 50 or 55 zone. There could be caverns to explore and maybe a dungeon, rare and elite mobs. Epic class quests, world bosses and maybe a scenario or two. At the end of it, a cool spec-specific reward, perhaps one that you could upgrade at max level? There are several zones they could use, including Silithus and Arathi, which both are underused right now. Another option would be to make it an island like Tol Barad, that is instanced.
Having revamped the 1-60 questing experience in Cataclysm, I’m not sure how eager they would be to do this. Still, as the game goes on they will probably have to come up with new paths to leveling. To many, it is still a source of fun and ultimately, keeps players engaged and subbed.