Masterfully made, as always. I would be very interested to see more dragons, I actually wrote an essay about them a couple of years ago. I can tell you that there are distinctions between the definition of a dragon. The main difference is that they are sometimes presented as highly wise creatures, strong and intellectual and majestic. The other (more frequently used) view is that they are vile and warlike, in which case the intellectual aspect is completely ignored. You can usually see what interpretation the artist has taken on from the way the dragon is presented in art.
Sorry for the late reply. The essay is not available online, although I could attempt to dig it out of some dark corner of my computer, and e-mail it to you. Yes that was my standpoint as well. It's interesting to see how prominent they are in literature - there are even dragons mentioned in the Bible. The initial origins of the concept however has been debated, and because they are deeply rooted in so many different cultures, no definite answer has been given.
You could send it to me? Great! It would be really interesting to read.
Scaly things have not been in favour of humans for as back as I remember reading. Now that you mention it the Bible also mentions the snake in a prominent way with Adan and Eve, prominently evil. Now imagine they were bigger, stronger and could fly (I don't know where the fire-breathing came about) and you have a formidable opponent.
There was a flying serpent in Mesoamerica though I cant recall what it did or if it was a god or something else. You are right though, dragons do appear in many different places.