It is confirmed. The Public Test Realms (PTR) patch 2.1.0 is open and letting fans test Black Temple. The screenshot provided by Midork @ Warsong realm talks about Deathwing and the experiments with the dragon eggs. The NPC seems to know about Nefarian’s defeat and the ruination of his plans. The master (Deathwing) wishes to continue the experiments his son was unsuccessful to finish.
Could this lead to the creation of the Infinite Dragonflight? Hmm …
Post a comment at our Warcraft Lore forum.
UPDATE: New screenshots of Black Temple are starting to show up. Teron Gorefiend will be in the dungeon. Various bosses have been shown in this European site.