This likely correct. Whilst talk of the factions ending or being dissolved has been common place for a while now, the evidence of such a move is pretty thin.
At the moment, the main evidence seems to be that this is where the war campaign MIGHT conclude and the UI upgrades that were added in 8.2. Whilst these are definite indicators that an end to the factions are possible, they are far from conclusive.
When 8.2 was being previewed last Spring, Ion Hazzikostas gave an interview in Forbes Magazine.
https://www.forbes.com/sites/hnewman.../#79b98484a0e1
"Newman: Something that y'all have tried on the battleground side is to have the mercenary system. Is there the possibility that something like that might apply for PvE play as well? That you could decide as a member of the Horde that you're going to raid Crucible of Storms as an Alliance player for the evening?"
That quote was from an interview in April. Whilst I am sure some will argue he was lying in order to obfuscate the change, there are easier ways to obfuscate a future change rather than offering a full throated defense of the status quo. As a lawyer, Ion has carefully parsed his words in the past, and saying one thing only to be shown to have been lying a few months later is the kind of mistake that would haunt Blizzard in future.Originally Posted by Blizzard Entertainment
We know from this interview that they think the faction divide is important. We know from the High Elf rejection that they think the existing races (with the clear exception of Pandaren) have strong ties to the existing factions.
And the entire war campaign ended with the reclamation of the soul of the Horde through Saurfang's sacrifice.
No. The factions aren't going anywhere. The 'last hurrah' for the faction war seems to be about settling the Horde and the Alliance into a permanent status quo vis a vis each other.
I predict we are going to have a situation where the core leaders of the factions are friendly and co-operative with each other. Each of the new threats faced by the Horde and Alliance will be dealt with co-operatively. However, outliers within each faction (Tyrande and Genn for the Alliance, Talanji for the Horde) will not accept the new status quo and they will justify war mode from 9.0 onwards, by asking players to declare for their faction and do what they can to hurt the other side. To my mind that is the likelier scenario.