Go to galleries here, on Renderosity, on dA, and maybe on Artstation, and do a survey of what's posted. Rendo and dA will probably give you the most generalized pool to work with. We're a smaller group here, and Artstation tends to be where the cream of the crop posts their best. Break things into categories based on basic mesh shape. For instance, underwear and swimsuit can be the same thing. Catsuits can be lots of different things with different textures. Also record what genre (fantasy, sci fi, etc.), type (pinup, portrait, action scene, etc.), and number of people and distinct outfits in the scene. If you have specific ideas about features, like zippers or buttons or sitting poses or twisting, record how many times people use them. If you have specific problems you're worried about eliminating, record instances of them appearing. Once you've gone through 1000 or so random images by random people (try not to get more than a set number by one artist), you should have a good ranking of clothing items, features, and genres, as well as some idea of how much variation people need per image.
You might also count the number of nudes per image. That way you'll have a relative importance of characters and hair to clothes.
Just speaking from my own survey that I did some time ago, almost all images had very little clothing, were standing there, lying there, or (rarely) sitting there, and were almost always so skimpy that complex clothing interactions aren't an issue. They almost never bent the torso very much. By far, most images do not use extreme poses. If a figure is wearing a full skirt, it is almost always standing there, not moving, sitting, or lying down. So it's much more important for a skirt with a train to twist and pool on the floor than to work in a variety of kneeling poses. And as much as _I_ love dancing and dance poses, they just aren't used by others much.
So sure, if it's important to you, spend a full week or even a month getting buttons not to deform. It does work to root yourself in your passion, if you can pair that with steady releases. Many have succeeded that way. But 99.9% of artists posting images don't care, won't care, and don't even twist or bend the body enough to notice much fine bending work. Remember, V4 had _terrible_ bending, and took several years to even approach having that fixed. People (as a group, not in specific) care much more about other aesthetics, and only care about bending when they aren't distracted by those.
I'm the queen of taking ages to work on features almost no one cares about, so I'm not trying to say anyone _shouldn't_ spend time on those things. Frankly, I don't know how to _not_ do that. If I could just whip out stuff that people buy in droves, I would, but that's just not me. So I totally respect if that's not you, either.
But the most popular dynamic clothing of all time had no detail, no groups, default stretchy settings, no UV maps, no built in morphs, and no textures. If you want to know what people like most, and find most necessary, go out and look at what most people use.
If you want to make high quality, gorgeous clothing with specific character and everyday use, that's great. But you risk everyone talking about how specific your figure is and how it doesn't have enough support. Where most figures fall down is being a specific creation by a skilled artist who focuses on quality in very specific areas, rather than a blank canvas that does the kind of simple, easy, quick work that 99% of users _and_ newbie content creators want. If you want to know how to support a new figure everyone will use as quickly as possible, I'd say focus on how game professionals texture (fast and realistic), focus on people posting images _not_ those of us in the forums who tend to be outliers and the most fussy of content creators, and follow the number one rule of paying attention to what customers do, not just how they self-report.
Because, by and large, people tend to be wrong about their behavior. Just about every study ever done on the subject shows that people do not accurately predict what they will do (especially when it comes to buying habits), and do not accurately report what they have done. That's why UX people have mostly switched from tools that involve self-reporting to ones that record what people actually do given different parameters.
In fact, try focusing the stuff that most people in the forums complain about. Because it's their popularity that causes the complaints. If skimpwear and characters that look similar but have slightly different coloring and features weren't so common in the marketplace and in the galleries, it wouldn't annoy us in the first place. What annoys those of us who push for more is the stuff that's popular but doesn't meet our standards. If it wasn't popular, we wouldn't notice it to be annoyed.
I might hate reality and teen angsty shows, but if you were starting a network, I'd say to get at least 3 of each to hook people in of all ages. And then another three that take advantage of the internet trifecta of funny and/or sweet pets, random feel good stories, and sex. Separately, that is, not all together.
High quality and unique is great. That's what I like to make, what I like to look at, and what I like to buy. But the most popular independent figures like Sara and Maya Doll, and even just not Vicky figures like Aiko, started off with loads and loads of quickie content, a few mid quality pieces, and a couple of high quality skimpwear sets. None of them started off with high quality everyday clothing with superior bending. Most _never_ got that.
My dad threw me in the pool when I was 6, and boom, I was swimming out of instinct. Of course, it was a shallow pool for children, but I was doggy swimming nonetheless. Looks like all mammals instinctively know how to swim from birth, but the issue with humans is to tame the fear of water. There is a possibility that people drown not because they don't know how to swim, but instead because they panic. In a similar way, people can die on dry land by being stomped over in a crowd panic - not because they don't know how to run, but because they panic. So it could be that people who have trouble learning how to swim could actually be just afraid of water. Food for thought?
Some people sink. My husband's family tried to teach him to swim this way, and he nearly drowned multiple times before they saved him. My father can swim, but he naturally sinks. My mother swam competitively when she was young and loved it, but she has to work harder than people who are more buoyant. I learned to swim young, but I couldn't float and had to learn to work with the water. It's especially common for people of color to not float naturally at all, so just automatically doggy paddling and splashing a little doesn't work. You have to learn how to really work with water, pushing against it to bring yourself up to the surface and above it if you naturally sink.
