This is just me writing down my thoughts here, I'm not suggesting anything directly but I'm just trying to put down some little personal thoughts, main points in bold:

-If this change is to be put in place, Human(oid) and Animal Art should most definitely be categorized differently. Given the demographics of the CS community, you're more likely to see animal artists. With that in mind, if any new categories are to replace beginner/intermediate/advanced/sketches, then Human(oid) and Animals definitely need their own categories.

-Relating to the point above: like I said about the CS demographics, there seems to be a lot of animal artists. These artists, however, may like to draw animals (fantasy or existing) in anthro form, or in other ways that aren't considered "natural" (unnatural coloring/markings, having body parts of another species etc). Sometimes it's refreshing to see just plain old animals just being natural animals. This could just be me being 'nitpicky', but perhaps an Animals category could be divided into "Natural" and I don't know what I'd call it, but something along the lines of "Furry-Centric". Like I said, I don't know what else to call it, but sometimes you wanna see a tiger and other times you wanna see your favorite artist's new sparkledog oc. I say this as a furry, by the way even though I don't look like one based on my own drawings, so if the way I worded this point happens to rub anyone the wrong way, I'm sorry in advance, but I don't know what else to describe it as. Or, scratch whatever I just said and perhaps categorize "sparkledog"-type and anthro art into Fantasy Animals, if that category is to be made. Again, I'm saying this as a furry, despite what my profile appears, so if this doesn't vibe with you guys I'm sorry. I don't know how others would like this, but I think this works. With this point, I think it's obvious that I'm also implying that an Animal category might need categorization into Natural and Fantasy or otherwise unnatural.

-If I read correctly, I think we're in agreement that a Combo board isn't needed, but with that said, if drawing a "combo"-type drawing, then the artist needs to be able to categorize it as they see fit, but still appropriately. If they draw a human family with their companion animal, for example, that would probably be best off in the Human(oid) category because the piece assumably focuses on the *human* family, and the companion animal happens to be a part of their family. In another example, a drawing of some herd dogs corralling livestock with a cowhand in the background would probably be put into the Animals category, because the cowhand is not the focus of the work. For this reason I think that a Combo board isn't needed, but some basic care needs to be taken by artists drawing multiple subjects when categorizing.