That was deliberate. From what I've seen, the Aserai face many of the same problem that Sturgia faces with it's very spread out and linear geography at the edge of the map. I don't think I've ever seen the Aserai take a single city outside of their strip of land in my 100+ hours of campaign, but honestly I haven't delved into them enough to comment on their units specifically. I do like their dual noble line with a heavily armored two handed axe infantry though, at least in concept.