Let's put aside the lore for a minute, although the Triglavians taking over the billboards, a communications device used by corporations and alliances to recruit new members, was a cute move.
With the addition of three new ships, the Triglavians will have the most unique ships of any pirate faction this side of Outer Rim Excavations. And ORE isn't considered a pirate faction. Here is a list of the Triglavian ships available to fly once the expansion hits.
Damavik - frigate (tech 1)
Nergal - assault frigate (tech 2)
Kikimora - destroyer (tech 1)
Draugur - command destroyer (tech 2)
Vedmak - cruiser (tech 1)
Rodiva - logistics cruiser (tech 1)
Zarmazd - logistics cruiser (tech 2)
Ikitursar - heavy assault cruiser (tech 2)
Drekavac - battlecruiser (tech 1)
Leshak - battleship (tech 1)
At this point in New Eden history, the Triglavians are not known to possess three key technologies known to the Empires, and thus capsuleers. The first is area of effect interdiction. The Triglavians know about webbing and scramming just fine, but we don't know about their ability to deploy warp interdiction bubbles. The lack of this technology means a lack of interdictors, heavy interdictors, and interdiction nullified ships like interceptors.
The Triglavians also have not displayed any stealth technology. As players also cannot use cloaks, perhaps Abyssal space precludes the ability to hide. But besides cloaks, the Empires also have ship classes immune to the directional scanner. So it is entirely possible that ships like stealth bombers, covert ops frigates, and force recons for ships that use cloaking devices, along with combat recons. In other words, no Triglavian black ops drops. Well, at least as far as we know.
The final technology is jump drives. If Abyssal space is anything like wormhole space, jump drives wouldn't work anyway. Thus, the creation of a powerful, battleship-sized weapon that out damages capsuleer battleships. Without a jump drive, that leaves out black ops battleships, capitals, and supercapitals, although the Triglavians are building something huge.
Also, we have not seen any evidence of the Triglavians possessing any tech 3 ships like the tactical destroyers or strategic cruisers popular with capsuleers.
So what's left? Command ships, the tech 2 variants of the battlecruiser, are an obvious choice. Since the developers are already on a path to creating both tech 1 and tech 2 ship classes for each sub-cap ship size, I could see a Triglavian marauder-class ship appearing as well.
But if CCP truly is looking at making the Triglavians on par with the empires in known space, then our tripartite friends really need industrial ships, like haulers and mining barges. Imagine what a Triglavian deep space transport would look like. Or the mining output of a Triglavian mining laser.
I've started to go off the deep end on the speculation, so I think I'll end the post. But with such an expansion of ships, plus the current focus on the Triglavians, I really wonder what the future holds for the ships from the abyss.