You said yourself, of the Star Wars series, that "Sith goes further back into time when Luke Skywalker was a little boy chronologically and historically speaking". Did you have trouble with seeing and understanding the 1977 "Star Wars" before seeing the prequel (Sith) that flashes back to how it came to be? Doesn't it even become more interesting to see the "back story" (Sith) later in the series, when you know what will come after? Wouldn't the back story be kind of boring if you saw it chronologically first and didn't already know who Luke Skywalker is? Would it mean anything to you?
There are arguments for both sides of this Narnia ordering question but strictly chronology is not a particularly strong one, if you ask me. Since Lewis wrote them with "The Lion, the Witch and the Wardrobe" as the 1st book and "Magician's Nephew" as the 6th, there are assumptions made in "Magician's Nephew" about what the reader already knows. Those things make no sense to the reader if he's reading "Magician's Nephew" first. For example, from a website noted earlier:
The narrator of "The Lion..." says 'None of the children knew who Aslan was, any more than you do.' But if 'you' are supposed to have read The Magician's Nephew, then you do know who Aslan was.
The charm of the opening of "The Lion..." is spoiled if you already know, from Magician's Nephew, that the wardrobe is magical; that the Professor has been to Narnia, and why there is a street lamp in Narnia. Similarly, the 'shock of recognition' in Magician's Nephew is spoiled if you don't know the significance of the wardrobe.
Those points coincide with my opinion, maybe because I first read them in the original order so I'm wedded to that. Like I said, others differ. But simply chronology does not seem to me a persuasive argument. There are many stories and series ("Star Wars" is but one example) that don't follow a strictly chronological order and many are more interesting for it.
Of course, we're not talking about that.