I notice this has been brought up before, but it always seems to get... derailed...
I don't want to tell anyone how to play or invoke real-life equivalents, but it strikes me there's an interesting argument on both sides if we can remain civil...
Watching the old movies makes it kinda clear to me that we're not meant to be rooting for the Imperials. But, hey, the question 'what is Star Wars' is a lot more complicated today than it was thirty years ago. SW has changed and gaming has certainly changed. I remember the early 90s, when games like Ars Magica, Shadowrun and Vampire Masquerade were in vogue, with PCs that didn't seem any different than the villains (and in D&D, the 'grimdark' campaigns like Dark Sun and Planescape).
I'm sure the EU has plenty of Imperial examples, and not everyone on the Imperial side is a depraved, sadistic monster. And yet, it's still a very repressive regime run by Dark Jedi. That would seem to require a certain mind-set as PCs. I can imagine even many evil types feeling that Alderaan was kind of over the top - all those resources wasted, not to mention the huge PR fallout.
I can't help but feel that it wouldn't be right simply to use the Rebel scenarios with the numbers filed off. I mean yes, the classes and things would fit, sure. A rebel pilot and an Imperial one are just ultimately flying different ships, they are not different classes.
But AoR seems very much about playing the 'ragtag irregulars against the overwhelming force of the Empire'. Isn't it going to feel different if the PCs are backed up by Star Destroyers? It strikes me that if I was on the Imperial side, I'd be much more worried about being killed by my superiors than the Rebels. The movies make a running joke of Vader bumping off his underlings, after all.
And I guess you'd have to assume that the PCs were at least some kind of elite unit, not Stormtroopers 700,316 to 700,321. And even then, I would imagine the logistics and general feel of playing the Imperials would differ considerably to playing the Rebels. The morality of it for one, obviously (Owen and Beru seemed to be a fairly standard workday for Imperial troops) but also the role of the PCs, and how they feel about being tiny, mostly unvalued cogs in a huge, ruthless machine.
I'm sure there are morality decisions to be made in any war, even by the Rebels (is it okay to blow up a Moff's family when attacking an enemy base?) but these elements would seem to be greatly amplified for the other side.
On the other hand, is it a good thing to have a theme for a role-playing game? In Edge of Empire, you're not playing the Hutts or Black Sun crime lords... or Jedi, or Imperials. That might make for an interesting game, sure, but you're supposed to be playing scoundrels. In a 'Lord of the Rings' RPG, you're probably not playing orcs or nazgul. In the Warhammer battle game, you can play an orc or skaven horde... but in WHFRP, having an orc or skaven PC wandering around in an adventuring band in the Empire would just feel silly. Is there a strength in having a set feel and theme for a game?
Just thoughts - I'd be interested in hearing from both sides as long as we can keep the arguments polite and keep away from real-world stuff.