It's really funny how we know nothing about this city yet, and still people already have opinions that are set in stone.

Confirmed: There will be at least one town that was once a Dwemer site. (Also: Steam Centurions are in, so there will probably be dungeons based on that theme as well.)
Probable: a) The screenshot shows Markarth Side and b ) it used to be a Dwemer site.

That's all we got right now, I think. If we go with the assumptions a and b, then that still doesn't say anything about a "new Dwemer architecture style"! There are civilized people living in that city. They will have put some work into it. The Imperial City was clearly Ayleid, yet it looked completely different from the ruins elsewhere, because people have used the available material, but built their own architecture with it. In the case of Markarth Side, they would have probably removed any strange devices and pipelines and built their own entrances to the tunnel system. I mean, that's what I'd do if I went to live in an industrial ruin.