IMO,the Arishok is simply the Arishok, he just spews crap about the Qun. He complains pretty much about the same thing. It never felt like an in-depth analysis, it was just whining about how the Qun is so much better.
Characters don't really need to have a metric ton of layers to be well written, though.
But I do agree the Arishok is a good rep of the Qun. That much, at least, is apparent.
This is so off topic
Then i guess its just a matter of opinion and how you take what he says. He always has something to say, that at the core of it, is true, the only reason no one outside of the Qun would follow it is because it means sacrificing freedom of choice.
Ex:
"There actions mere symptoms, your society is the disease"
"Look at you. Like fat Dathrasi you feed, and feed, and complain only when your meal is interrupted. You do not look up. You do not see that the grass is bare. All you leave in your wake is misery. You are blind; I will make you see!"
Then there's the conversation you can have with him asking about the Qun, he trust me, he definitely analyzes why their societies are different, its up to you whether you like it or not. I agree that characters dont need tons of layers to be a good character but, it helps and in regards to Fenris, he was associated with being dull by a significant amount of people because he lacked any complexity