Women (or men) don’t have to be naked to be appreciated for their beauty. The need to see them naked infers the intent is sinful.
Sure, if subjective beauty partly is derived from shape, complexion, bone structure, even a clothed person can rightly be called beautiful. And certainly the face is the most important aspect of subjective beauty, which we all uncover.
I’m going cautiously here. I don’t want to dwell too much about a “need to see [nakedness]” since that implies a slavery to passions and lust which is sinful. You’re probably right, although the sin could still be less sinful compared to worse habits, so it could still be an improvement in some people.
But let’s change your statement to a “desire to see nakedness.” Now, I think we’re dealing with a neutral concept, with either good or bad ends. Let’s explore the potential good ends.
Why do we cover the sex organs? Partly due to shame, partly due to protection and prudence (we’re fallen and prone to sin). Note that all of these reasons are not natural reasons, they are in response to an event, original sin. One natural reason is curiosity, which while good, can lead us astray (here, with lust) if not checked. In our Edenic state we were naked, and it was good. In our eschatological state, our clothes are not likely to be raised along with our bodies. Our eternities will be naked too.
Our naked bodies show our objective beauty that everyone has. Our parts have such harmony, allowing motion and grasping. Our sex organs allow reproduction and nurturing. It is very admirable and therefore beautiful. Our naked bodies are made in the image and likeness of God, and in the natural world (creation), are the closest glimpse of the Trinity God we can see. Each and every one of us, friends and families and enemies, has this beauty, and it is amazingly good. This is harder to appreciate when we are clothed, so some of the good desire to appreciate the naked body stems from this line of thinking.
Of course, some of us were gifted with subjective beauty too. Because of the Fall, most good Christians with such beauty keep themselves clothed except with their spouse and a few functional exceptions (shower, doctor). To dwell on marriage is a bit off-topic here. However, a few people are willing to show their bodies as a gift to the rest of the world with the proper precautions. We should never thrust nudity on the world, which is why all public “indecency” laws should be upheld and several warnings need to be placed before mass media programs. But for someone who is properly disposed not to lust (a pure person) or needs to relearn the goodness of the body from years of past depravity, displaying nudity in a controlled environment with a context that lifts the minds and hearts to God is good. We appreciate the work of the artist and the gift of the model.
We desperately need good Catholic artists and models in this world who understand the theology of the body to portray nudity in an uplifting way. Right now, the pure or recovering Catholic likely has no great options in the modern forms of art unless they live near a modern art museum (even then, not so much), but that’s beyond my knowledge.
In these cases, the desire to see one naked is no worse than the desire to appreciate the beauty of the sky or the grand canyon which are far less beautiful or the desire of any other form of entertainment that is morally neutral like a play or sports. In some ways, this desire has way more potential upside. So if by “need” you meant “desire” I have to give a cautious disagreement.
If you want some lengthy JPII or other quotes along these lines, I think I can find some for you.