Completely agree with all your points, and yes, as far as I know, all languages basically refer to the Earth, sun, moon, and stars as if we were standing on a dinner plate, and the sky were a concave shell above us.
That said...
Some part of my subconscious has been kicking around ideas about what is 'natural' for humans insofar as we *do* strive to improve ourselves, and in particular to see things from other points of view, and consciously (and subconsciously) change ourselves based on that. There's no question that one of the great strengths of humans is that we *can* (when we try) understand other points of view, and even, to some extent, adopt them. You mention, for example, the coyote: naturally we wouldn't expect a coyote's perspective to be like a human's, and we would not expect a coyote to try and adopt a human perspective (although certain dogs do a very good job of it), and we would not ever expect any human to completely grok a coyote's perspective. But some humans, with years of study, do come to understand coyotes extremely well -- better than, say, rabbits understand coyotes, or bees understand coyotes. And because of this plasticity of mind (which goes hand in hand with the neoteny of our physiology), the question of what is 'natural' for human beings is rather complex.
To be specific: for humans who grew up and lived all their lives on a space station orbiting the moon, it would be completely natural for them to adopt new words for the motion of the sun, words that might have more in common with the 'objective' perspective than what most languages use. (Or perhaps not: they might still use perspective-centric language, e.g. the sun is "coming out", i.e. from behind the Earth or the Moon.) This wouldn't mean that they were unnatural humans, nor yet that they were less anthropocentric. But they'll have adopted a perspective quite foreign to any other species of Earth life.
So... since this is probably rather muddled, let me summarize. I completely agree with you, AND I think it's interesting to note that we humans have this plasticity of mind that makes it difficult to say exactly what is 'natural' for a human being. And as we alter our environment through developments in technology and culture, our neoteny and plasticity will only increase. It will be fascinating to see what strange ways of being human we develop in the next ten thousand years. :-)
Very excellent points. I don't think I have anything to add, other than that I think appreciating the plasticity of human nature and human language means, to a certain extent, explicitly allowing and making room for that plasticity. While that might mean sculpting and shaping our language consciously in some ways, it also means allowing language to evolve naturally. In this case I do not think it means excising certain terms completely and attempting to replace them with others in accordance with a predetermined ideology, especially not one that posits that it is fundamentally problematic to even acknowledge our human perspective.
In the other comments responding to Rua Lupa's post, some readers have offered very poetic alternatives, and poetry is exactly the right place where this type of language play is at its best. (There are plenty of examples where poetry has been the source of new words or phrases, too, so in that way poetry is not only the perfect place for language play, but the most nourishing soil for the evolution and growth of language as well.) I am by no means saying we shouldn't experiment with language or explore its depths or flexibility. Please yes, let's do.