Unstable elementals and the alliance
Honestly we haven’t been given much any information as to why there are unstable elementals tied to the vents (unless it is just an effect on the environment much like the storms).
I wouldn’t be surprised at all to learn that they are drilling their way underground to Hoelbrak and the Black Citadel, but again it’s just speculation.
I figured since the flame legion likes messing with unstable magic so much, they were calling forth the elementals , but tunneling makes more sense I guess lol.
The elementals may just be attracted to the ruptures themselves. We are told in Metrica Province by several asura that elementals are attracted to the energy conduits of the Thaumanova Reactor that are scattered over the area, and also they seem to like popping up near the weather krewe research stations (I know those are air/lightning elementals, but same principal applies, they are attracted to disturbances in elemental power). The vents themselves, like you said, could be products of whatever those naked-mole-rat -communists are doing underground.
~Surrender fiend and you will get an easy death
~I could promise you the same…but it would be a lie…
The tunnel theory does seem reasonably likely. My money would definitely go on some kind of underground construction, and the fact that it’s approaching Hoelbrak and the Citadel is probably not coincidence – it feels like an invasion plan.
As for the elementals, the first signs of trouble – before we knew about the dredge and Flame Legion being involved – was stormy weather. Blizzards and dust storms were driving people from their homes before invaders showed up. I would assume that whatever this ‘Molten Alliance’ is up to, it’s messing with the environment (whether through magical means or just as a side effect of underground something) and the ‘unstable elementals’ are an effect of that. The steam ruptures may be causing atmospheric problems. We’ll have to wait and see!
And I suppose that now we get veteran elementals (I am sure they were not part of the rupture event before) means it is getting stronger / more powerful / destructive.