I can't get behind any Star Wars game that has ever come out fully.
The best setting information is still WEG. That said, I agree with
@MGibster that Wookiepedia is the best source you are going to find. The WEG books however are very good as indices to help you find things though, as to really get the most out of Wookiepedia you have to already know the lore pretty well.
While I do like D6 a lot and WEG has to be praised highly for the quality of the IP that they produced, the system suffers from a number of flaws. Major Quibbles:
a) There is a general lack of editorial control over the mechanics such that every single book that was published had different ideas of balance and gear, vehicles, ships, and so forth published for the system over the years are all over the place in terms of balance, utility, and compatibility. Powered armor is a particularly egregious example, as different authors employed at least three different rules subsystems to implement it with varying degrees of just how overpowered it would be - which is especially weird when it's all upside given that it plays little role in the lore.
b) It's a skill driven system that has really poorly thought-out skill space in some cases.
c) Some subsystems like the interaction with Capital Ships and Astrogation/Hyperspace are really poorly thought out.
d) Race construction rules/templates are just horribly broken as presented with races all over the place in terms of power level and a general lack of understanding as to what a drawback is rather than a benefit. As written, there is little reason to play a human despite how homocentric the setting actually is.
e) Much as I love the soak rules and wound track conceptually, the lack of hit points makes planning for actually challenging encounters very difficult. Combat tends to be either extremely easy or extremely deadly with no real sweet spot. This one is almost becoming the deal breaker for me.
f) The kludge fix for 'e' involves spending XP as narrative currency, which involves the horrible tradeoff of either trying to stay alive now or falling further and further behind in the future.
g) Force users have that zero to demigod curve associated with D&D wizards where they absolutely suck at any level of play you are likely to reach, but then in the long run eventually break the game wide open.
h) The rules for all-out movement make more sense for characters than they do for vehicles.
Minor Quibbles:
a) While I get that it had its problems, treating speed as a skill in 1e had big advantages over fixed values seen 2e when it came to running chase scenes. Worse, the rules migrated to fixed values without handling scale well.
b) The rules for torpedoes, shields, and several other ship systems don't really work well.
c) Ship combat minigame could be a lot better. Compare the miniature game for example.
That said, I'm not sure any more modern rules set is necessarily better in this regard.