I've been curious about this myself but maybe they didn't have the time or space to add them? It also seems strange to me that it only took a few centuries for them to turn into the twisted monsters they are, wouldn't that take considerably longer? As for dlc I doubt very much they will expand on Snow Elves but who knows..
The Dwemer disappeared thousands of years ago, and before then is when the Dwemer enslaved the Falmer. They changed a long time ago. Much longer than a few centuries.
The Falmer may have actually been the ones that built the Nordic ruins (see Saarthal, which existed before the Nedic people of Atmora arrived), which housed the Eye. The ruins that Nords call their crypts may have actually been the homes of the Falmer before they were pushed away. Where the Nordic dead lie may actually have been beds for the Falmer, but were adopted as a place to put the dead followers of the Dragon Cult. Nords clearly do not build in stone, and I do not think they ever did. The advantages of the crypts are far too great to cast them aside in favor of cities out in the open. Yngol's Barrow and the Palace of Kings (Windhelm) are two exceptions that I can think of, and those may have been altered slightly by the Nords from an original Falmer site. Yngol's Barrow is clearly FAR less stony and is less perfect compared to the other so-called "Nordic" ruins. The only palces that heavily resemble the other ruins is the throne room where Yngol's Ghost resides and the area with the pillars prior to entering the throne room. Those may have been original Falmer designs that were adapted to Nordic use. The Palace on the other hand, was constructed by Ysgramor himself, but the same theory applies to this that is stated above and I think it was the head of the Falmer kingdom, almost completely opposing their Dwemer cousins, whom they called upon to aid them when they were pushed out of their land. Ysgramor using that place as his throne is symbolic of him completely defeating the Falmer by taking their throne and capitol as well (assuming my theory is correct).
Nords always seemed far more about direct power rather than sneaky traps, which the Dwemer use, so the Falmer (being cousins and perhaps being somewhat relatable in intelligence) may have actually been the ones to make the traps.
If that explanation isn't plausible enough for you, then maybe they were nomadic? If not that, then perhaps their architecture wasn't wrought of stone and metal and was perhaps simple wood (which is easier to work and keeps cold out much better than rock) that was ransacked by the 500 on their conquests.