Currently, even the densest and most populated of towns are relatively cleanly, with the worst I've seen being baskets being left everywhere after someone builds them for LP. From what I heard of city life back then, hygiene was virtually non-existant, and since people generally disposed of garbage of all types by dumping it outside, it was near impossible to travel on foot without stepping into the feces of one species or another. Giant piles of filth eventually attracted rats of all sorts that spread disease and ruined food. Rats then spread diseases to animals as well as people, rabies turned regularly timid animals into dangerous ones, meaning they had to be dealt with or risk harm to the citizens.
Therefore, I suggest that densely populated areas should have to maintain their cleanliness or suffer the consequences of a filthy village, i.e. drop in productivity, disease, unhappiness, etc. I'm sure the rest of you can figure out what general messiness and dirty jobs should exist.
Also, it'd do the newer players some good to have weak animals also spawn in lower level areas. Namely, chickens, cows, cats, dogs, pigs, and sheep, so that new players can practice their combat skills (Supposing that the current LP system will get scrapped in favor of one requiring "hands on" experience - meaning making baskets and roasting meat will not teach you how to kill bears with your bare hands) and gather materials without having to grind massively. Their more dangerous counterparts: hawks, wolves, buffalo, mountain, lynxes (oh god), wild boars, and wild goats; would exist in wilder areas and give better quality materials (Assuming the item quality system works as planned).
More later, but this is generally how I see it.