Even though there have been many threads about what the next expansion will be, I just wanted to post this one to offer some concept ideas IF it is Burning Legion themed.
If indeed the next expansion is themed around the Burning Legion invading Azeroth once more, how plausible do you think it might be if Karazhan makes a reappearance? Why Karazhan? Well, there are a number of reasons/pieces of evidence that make it an ideal spot for the invasion to happen in.
1. All of Azeroth's Ley lines lead to a location under Karazhan. All of that power could easily be used to open a portal into the Nether.
2. Some traces of the legion might linger on from when Sargeras occupied Medivh's body.
3. Netherspace: It really hasn't been clearly defined by anyone. It might be a gateway into the Twisting Nether itself, a twisted copy of Karazhan, or a different dimension entirely.
4. Prince Malchezaar: Why was a random Eredar at the top of Karazhan? That fact has been somewhat shrugged off. They're relatively high ranking members of the legion too. Maybe the Prince was given the task of prepared the tower as a point to launch the invasion with Netherspace acting as the medium to do so.
5. Deadwind pass has been practically empty and devoid of any meaning since the start of WoW, it could be given a purpose. Maybe it might be a daily quest hub? That crypt area could finally be used as an area the Legion is trying to open more portals in.
6. Some of the characters involved in Karazhan's past affairs would have the opportunity to be in the spotlight once more, Khadgar especially. Maybe it's time for him to show us exactly how much he's learned from the Naaru in Shattrath? Also, it might be time for him to stop giving that terrible tour of the city quest. No one knows what happened to Medivh either after the end of Warcraft 3. He might make a reappearance even though he intended to "take his place among the legends of the past".
7. Karazhan has simply too much back story to remain unused for much longer. In no ways am I acting as a Karazhan fan boy. Sure, the raid was great, but from a Lore perspective it didn't really explain much and was more of a filler raid.
8. Karazhan could also be used as a pre-expansion event. It could be re-vamped if Blizzard decided to.
9. And finally, even though this may be a far stretch, one of the whispers from the puzzle box of Yogg'Saron is "The giant rook watches from the dead trees. Nothing breathes beneath his shadow." It would make sense if the giant rook it's referring to is Karazhan, but who it Yogg referring to by saying "his shadow". Many of the other whispers from the box refer to the Old God N'Zoth underwater. Is it also N'zoth Yogg is referring to? Or is it someone else? Sargeras? Medivh? Or someone unknown.
Based on all these reasons, how plausible do you think that this concept might potentially take place in the next expansion?
Note: Please don't just post comments like, "Kara was the best raid evar and it should come back. Kara 4 lyfe. TBC rox." Keep it about ideas for how the Legion might come back into Azeroth/thoughts on Karazhan.