Saying they are no more complex and adapted than any other organism sells them far short. Yet they're more stubborn than a mule, somewhat slower than a horse, they smell worse than either, and they'll spit on a person like a llama. They've been known to bite. Their shape is not is amenable to riding although they are used as mounts. So there are things one might really want to change before spending a lot of time with one.
So those feet that are great on sand were made for walking on snow covered ground.
Likewise food is scarce in both the arctic during the winter and in the desert.
But if we focus on vertebrates, they are all so very very complex and adapted. Everything you've listed for a camel is at best a cherry on top. All other vertebrates are within a couple percent, and many of them have feature lists just as long.