Nope, the timestamp here https://www.youtube.com/watch?v=OmgI...youtu.be&t=454 is new, young velen and the demons coming down on the draenei is from nothing in Legion.
I honestly have no clue what point you're trying to make here. Whether they announce it now or Blizzcon, it doesn't change how much they've worked on.. and even if it is November, so what? It could be 9 months, it could be 12. What we do know is this time they really have said they're going to fill the gap to the next expansion satisfactorily. We'll just have to wait and see about that.
We have a Vindicaar arriving on Argus (or crashing down?) cinematic, Xe'ra death cinematic and an Antorus final boss cinematic coming up. Unless that first part of the teaser is taken from one of these cinematics (which I doubt, since flashbacks are all in cutscenes) then it's a safe bet that's from 7.3 patch trailer.
Why is how long the expansion announced after an announcement relevant to when it's going to be announced this year? If it gets announced in November, it may take until next November. So fucking what? Who's even talking about time from announce to release anyway? he big debate has been where will they announce it. Feels like you're on a different track.