I think I've explained reasonably well.

They're setting out the rationale in that section for why they believed Hrothgar did not serve an already existing niche (putting aside whether this is rooted in reality, since Roegadyn have a similar build), whereas Viera men would fit into one and thus would not fill this niche they perceived to be "missing". All they're really saying is that they're closer to Elezen and so would not add as much variety. My point is that they could easily deliver on a physique like the second in the below imagery and nothing about it would be inconsistent with the adjectives they used.