The world does indeed contain some amazing things. The human body ? Pretty amazing. Especially Salma Hayek’s. But is the human body designed by an all-knowing master engineer who preferred (and continues to prefer) us to all other living things? Probably not.
Proper engineering involves taking into account the environment in which the “thing” must operate. If you want to build a car that operates in the Northeast, you have to protect against salt deteriorating the underside of the car. If you build a universe solely for your favorite pet, it would be a poor use of resources to make that pet unable to breathe anywhere in that universe but on one planet. And if you did decide to do that, you don’t make that planet 75% water if you don’t design your pet to breathe in water or at least swim worth a damn. And if you did decide to make your pet breathe oxygen and not water, you don’t make it so incredibly damn cold or incredibly damn hot in so many of the already scarce habitats for him AND make him one of the few creatures that doesn’t have thick body fur to keep him free from freezing or sunburn. Though apparently you might want to make that fur grow only on his face to keep him itchy and give his mate something to complain about. But you wouldn’t make him require water to drink and then force him to find the tiny fraction of his planet’s water that does not contain salt (which would of course be fatal!) Unless you’ve just got an incredibly sick sense of humor, that is.
Proper engineering must also take into account the lifespan of the object in question. If you’re going to design a structure like a football stadium that will be torn down and rebuilt as soon as the sponsor stops paying for naming rights…maybe you cut a few corners. But if you know that your pet creations are going to live on for many thousands of years until you decide to come down and destroy them all on a whim, you have to plan for some longevity. You don’t give them useless organs that will be hanging around waiting to burst and spread toxins inside their bodies. You don’t put poison sponges in the back of their throats. You don’t make too many teeth grown in their overly cramped mouths, requiring surgical extraction in the majority of the population.
If your main goal is for your pet species to multiply and produce more adoring fans for you and your engineering genius, you don’t create them in such a way that makes it only likely to produce offspring during limited periods of time. And only when wine is involved. (And you also don’t spread the word that doing that is “bad, bad, bad” either, because that gets a bit confusing.) And you don’t design the male’s reproductive seed to be so incredibly temperamental that it can’t even survive inside his own body. And an incorrect choice in undergarments shouldn’t prove fatal to the species. Because if you require it to be stored in a sensitive dangling receptacle in front of his person, it’s going to get rocked quite a bit during sporting events and interactions with prospective mates. Even the lowly turtle has a shell. That couldn’t have been repurposed for scrotal defense? How about retractable genitals in general? It worked for Corvette headlights for all of those years.
Speaking of genitals and their proximity to the our rears… Even the most backwards of county fairs know that you don’t put the cotton candy stand near the row of Port-o-Potties.