Also, I take "core rules" to mean all the rules needed to play the game, not every class/profession that will ever be included, so I think I misunderstood. That may just be because I'm normally a D&D player and I'm used to additional classes being released in later books. So long as I can run a full campaign off the core books, I'm good with it. Of course, D&D also makes you buy 3 core books just to have the information you need to run a campaign.
Okay, if you're new to Star Wars RPG's, here's a bit of comparison to how the prior editions ran things.
Both WEG and WotC Star Wars had everything you'd need to run in one book. WEG only had the Rebellion and New Republic eras in existence when they were published, but they did at least touch on New Republic materials in their later core book (2nd Edition Revised and Expanded). WotC made sure to have support for the prequel/Clone Wars era in their core books (to the limit of the films that had been produced at the time), and included at least bare-bones stats for the New Republic and New Jedi Order eras in their core books.
WEG had everything you'd need to make pretty much any character in the core rules. Later books added rare or highly specialized skills (Brainwashing was in the Truce at Bakura sourcebook, for example), and when later books or comics would have force powers not seen before they would be covered in the sourcebook for that book/comic (also, one of the later books, the Tales of the Jedi Companion, the sourcebook for Old Republic-era play, included every single force power in one book. However, the core rules were sure to include every force power from the actual movies and a few from outside the movies in it. You could create anything from a raw trooper or Luke-training-under-Kenobi all the way up to Yoda, Vader and Palpatine from the core rules (although more detailed rules for martial arts were in a later sourcebook focusing on special forces, and the official stats for Yoda and Palpatine included some of the force powers from later books, but you certainly didn't need them to run most encounters)
WotC did make their initial two editions of Star Wars to be very similar and compatible with D&D, to the point that I know people who ran crossovers with only mild conversions (importing D&D monsters to be creatures in Star Wars, or using Star Wars rules to represent people from the future or a technological civilization). They had all the basic classes in there (Soldier, Scoundrel, Scout, Noble, Fringer, Jedi Consular, Jedi Guardian, and they added Tech Specialist as a core class in the Revised Core Rules edition), and some prestige classes (Bounty Hunter, Officer, Elite Trooper, Starfighter Ace, and made Jedi Master a Prestige Class in the Revised rules, where previously being a Knight or Master worked like old-school D&D level titles, where you became a Knight at 7th level and a Master (or Sith Lord) at 13th level).
Yes, WotC produced LOTS of prestige classes for d20 Star Wars, but they were often very redundant. You didn't need the Imperial Moff class to represent a Moff, when they could easily be modeled as a multiclass Noble/Soldier, maybe with the Officer PrC. You didn't need the Naval Officer class when there was already the Officer PrC in the core rules, and so on.
You could create anything from a new padawan or Luke-under-Kenobi as a 1st Level Jedi Guardian or Jedi Consular, all the way up to Yoda or Palpatine (20th level characters, although Palpatine was a multiclassed Noble 3/Jedi Consular 17 under the first version of his stats). The Jedi classes were also used for representing Sith too, since it's a very similar skill set, and even in the movies Qui-Gon refers to Darth Maul as "well trained in the Jedi arts". A later sourcebook added several Sith-specific PrC's, but you didn't have to have them to create Sith.
So, all the prior Star Wars RPG's included rules to create everything from new Jedi all the way to Knights and Masters (or Sith Apprentices and Lords), and support for all the basic character archetypes in one single book of their core rules, and included at least token support of the various eras that existed beyond the movies at that point.
It doesn't even include EU material by default (there's a short section basically saying it's up to the GM whether or not to include it, but that's about it). I haven't really looked too much at the third book. I would assume they take place either before or after the original trilogy, during a time when Jedi were common enough that having Jedi characters running around doesn't break canon (assuming you're concerned with that).
Yeah, I'm a huge fan of the EU, and still rather grumpy (if not outright bitter) at the treatment of the EU under Disney. I'm also a fan of canon, so my games tend to stick fairly close to the canonical Star Wars (or, what was recognized as canon before April 2014). The fact that the EU was basically created originally for the d6 RPG to flesh out the setting beyond the movies to the point that it could be a viable gaming setting really ties Star Wars RPG's and the Expanded Universe together rather closely.
