for me here is how I broke this down:
S - I don’t dislike any of the villagers in this species, several are favorites and am more inclined to like villagers of this species even if they have some details I am not fond of (aka Flurry’s blue eyebrows/ winter theme design)
A - multiple faves come from these species and/ or I am more inclined to like a villager just because they are this species. Considered putting deer up here because I really like fauna, fuchsia, and Deirdre. But on the other hand I really dislike Diana, a lot.
B - like these ones, but either don’t have top level favorites or don’t have enough experience with them to rate them higher. I suspect ducks, dogs, and maybe even squirrels could move up a tier if I had one on my island.
C - also okay, and there are some members of the species i like -Alfonso, zucker, and Egbert come to mind. But overall not particularly interested in them for whatever reason and tend to pass them up while choosing villagers, even when I like certain specific designs (ie papi, Paolo, bree and savannah), so something is not clicking for me.
D - no interesting these, and slight aversion to the overall design. Bulls are there mostly because I can’t really immediately think of any bull villagers off the top of my head (whereas cows I like some of them and remember they exist). I have softened somewhat in the wolves but I still just do not like them as my immediate reaction.