Nothing, but I personally would have a hard time finding such a civilization as relatable as a human one, because the altered physiology (and likely psychology as well) would make such a civilization very different from a human equivalent, or at least it should.
The same would be true with dwarves and elves, by the way. The only difference would be the prevalence of cultural guide posts for them in the literature; the cultures in question would as you say be quite different, and harder to relate to.
In short, I don't see the "superficial" differences you're referencing as all that superficial, not if you're trying to take it seriously.