I may be using the term loosely here, but if we apply the meta-gaming to the story, I think we can draw a couple of conclusions.
First, it is clear ANet is pushing the community to defeating bigger and badder bosses.
Second, it is also clear ANet has learned that these encounters are only feasible with distributed tasks (to avoid lag and zerks).
So, the next boss will be even bigger and even harder. Since dragons are way cooler than some giant annelid, it doesn’t take much reaching to conclude there’s going to be some kind of big distributed dragon fight in our future.
OK, so it’s safe to assume we’re going to have a big dragon to fight.
Which one? Well, there’s Jormag, Kralkatorrik, Bubbles, Mordremoth and Primordus.
The hints given in the teaser metronome suggest something underground, either below the surface or the ocean.
That eliminates Jormak and Kralkatorrik.
The thumpers are designed to search for something, as told to us by our Asuran friend after we killed the Marionette. Let’s assume she’s correct – it would be prudent for us to do so.
OK, so Scarlet is looking for something under the earth, or under the bay. That eliminates the possibility of Bubbles, since she’d be looking in the ocean.
Now the question is: Mordremoth or Primodus.
Everything up to this point has suggested Primordus is the big baddie among the elder dragons.
If they go for Primordus now, that means that ANet has given up the ghost on GW2 and is going for the throat. (i.e. expect no more expansions after that) Since they are just now opening up China, I’m guessing ANet is planning for at least another 18 months of development for GW2 – perhaps even 2 years. So they’ll save the whole Primordus and dwarf story for later…most likely.
Based upon this logic, I’m going to rule out Primordus, leaving Mordremoth. Combine this with the fact Scarlet is a Sylvari and most closely associated with the jungle dragon, I feel it’s safe to conclude we’ll be fighting Mordremoth next.