If the worst thing about them is they leave you wanting more, then I think it's safe to say there are bigger things to worry about when it comes to CoC2 writers.
Now if that was a critique of their bedroom performance...
As to Agni, she's... fine... very barebones, barely any content, nothing really unique to the game aside from her introduction and concept, but then she's another character who falls victim to the intro, 3 sex scenes and done, trap.
I'd still rank Berwyn's end as worst B content, but that's because of the baggage surrounding it more than the writing.