Gotta say im pretty excited Azshara is one of my favorite lore characters and with Thal'Dranath being "Reworked" all signs are pointing to Azshara and her master N'zoth being next on the chopping block i will post reasons below you tell me what you think?
Lets begin with Blizzard quotes from the recent dev Q&A
General
"The team has learned their lesson and accepted that they can't produce an expansion faster, so the plan moving forward as they start working on the next expansion is to make sure Legion has a lot more patch content.
"They want to build on the stories that they are in the middle of telling in an expansion, giving players something to do while they work on the next expansion"
Thal'dranath
"Thal'dranath will not be part of Legion"
"It won't be a reduction in content delivered to players, just that the team had a better and way cooler idea"
"Thal'dranath was yet another ancient elven ruined island that has a heavy Legion presence. There is already a lot of that in Broken Isles"
Heres we go.
Thal'dranath is a ancient eleven island filled with who knows what kind of mystical artifacts of power located in the south most part of the broken isles in the proximity of both many islands still unreleased to WoW Tol'Borad,Balor,Zul'Dare And the maelstrom to the west which hosts more Fabled lands and worlds like the great troll empire of Zandalar (Or Whats left of it) and the naga kingdom of Nazjatar and to the south Plunder Isle!
Blizzard said that Thal'Dranath will not be part of "Legion" that it was going to be yet another eleven ruins filled with demons and that they had a cooler idea, they also said they want more patchs to reduce content drought
And my Theory
Blizzard has already stated that Azshara will cameo in Legion that will be racing her for some kind of titan relic we know well be fighting xavius in legion in the emerald nightmare it is my belief that Thal'Dranath will be used as a end legion patch as a sort of prequel to the next expansion it will be naga controlled with probably some old god things happening there may be a 5man some events a scenario maybe even a filler raid (Doubtful) but what what we see and learn during that patch will give us a glimpse of the evil to come and will give Blizzard a decent enough gap to continue working on the next expansion.
As we have had 2 expansions in a row of legion and blizzard is quite well aware of the amount of people who want to see her
Im very confident in saying i believe the next expansion will be queen Azshara and N'zoth tieing the loose ends from cata bringing justice to N'Zoth for the tainting of the emerald nightmare and the corruption of Neltharion the Earth-Warder also known as Deathwing.
Thal'Dranath is located in the perfect spot for that expansions prequel
And for the people who hate water zones... my guess is Azshara gets her hands on something very powerful that allows her to raise Nazjatar from the depths of the sea
Locations
Could honestly range from
Tol'Borad, Zul'Dare, Zandalar, Balor, Plunder isle, Nazjatar, Undermine,Tol'Abim all of which capable of having subzones
Lore Map: http://i.imgur.com/YY73r3R.jpg
What Mobs would we face?
Trolls,Old God minions,Naga
Now this is just a theory and wishful thinking honestly... No need to be rude or toxic