well, for starters, no "you're not showing those parts, but she could be nude" rules.  then no, "her genitals and nipples are covered, but it's not technically clothing."  and no, "well, if you try and look for it, there might be the outline of a nipple."  basically, the same rules that apply to to movies (see splash), tv (see mtv, baywatch, the o.c., etc.), and print (see links i've posted).  even back in the day they allowed fig leaves. 

you're (collectively) completely out of step with rules for mainstream media if you're pulling thong shots.  tv and movie ratings are somewhat arbitrary, but they're a lot more consistent than things are here and now. 

you keep talking about with what people might not like to see. there's a lot of art here i don't like.  i don't have a right not to be offended.  i've sent co-workers to this site without any shame before this rule; and i've sent my parents to see my gallery at rdna after this rule.  to be honest, my friends and family would react negatively to,  "oh, she likes that kind of site," because it's a place where art is, by and large, very safe.  very in the bounds.  almost no one takes risks or tries to say anything daring with their work.  the new rule only amplifies that, while rdna, which doesn't even have tagging on nudity, promotes daring.    i don't think that's a coincidence.

i'm not saying that changing the thumbnail rule is the only solution, but there's definitely been a chilling effect on this gallery.  more and more, i see people post, "i tagged this nudity because i was afraid it would get pulled."  people are getting fearful about posting under the new rules.  if you actually want a gallery that's more than chicks in chainmail and pinups, you're going to have to do something to counteract the atmosphere of censorship.  not that you should want people to express more creative ideas or do work that's more conceptually daring.  maybe what you want is a lot of safe art that's well executed.  that's cool, too.  then just come up with some actual visual rules (not perceptual ones), and be exceedingly open and consistent about what you do and don't allow.  frankly, i think in that case it would be better to go the daz route, and just make it a contest with submissions and stop trying to control the look of an open gallery with restrictions rather than rewards.  if what you want is to compete with other galleries for illustrators, designers and artists in general rather than just in 3d or poser specifically, then something needs to change.