At this point it's building past "where there's smoke, there's fire". They have been using portions of SoD to tie some additional lore threads into the mix for TWW, specifically with Xal'atath.
Goblin patch incoming, and methinks it's Undermine.
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To be fair though, a lot of Teriz's speculation on a hypothetical Undermine patch revolves around squabbling cartels. If they impliment Undermine as a large city zone, we may see many subfaction areas that are more open to us, and others that aren't.
Nighthold is a good example. We're fighting Legion aligned Suramarians to liberate Suramar in totality. Something very similar would be the case in this situation I think is Teriz's belief.