Regarding species in supplemental products.
If we assume each one of three core rulebooks offers six unique species to its product line (i.e.: We've seen Rodians in Edge of Empire, but not in Force and Destiny, so I consider that example fair game.), I submit that we will not see repeats within the same product line. For example, I do not expect to see "Zabrak" in Endless Vigil, but they could pop up in any Edge of the Empire or Age of Rebellion books. We have seen a strong species whose book-crunch seems to align with at least one new career.
This is already confirmed, if not by the Devs than by precedence. The only repeated species we've seen have been repeated across different lines:
Bothans - Edge and Age;
Droids - Edge and Age
Duros - Edge and Age;
Gran - Edge and Age;
Humans - Edge, Age and Force;
Ithorians - Age and Force;
Lanniks - Age and Force;
Quarren - Edge and Age;
Twi'Leks - Edge and Force;
Even though the lines are essentially one and the same, FFG is looking at each one as its own consolidated game. Meaning that, while they may repeat information and mechanics and stats across different lines, they won't do so inside a single line.
Regarding Fixed Species.
With any confidence, tell me that printing Lanniks TWICE suggests careful planning. I believe the species was initially flawed, or somehow abused in the rules as written, or deemed too weak. In any outcome, their inclusion in Keeping the Peace was a serious surprise. However, I like the changes to the species, and expect more highly-playable species to get edits in future books. This idea could help explain away any remaining confusion about female Devaronians, for example. I think FFG is trying to do this editing already, with Lanniks and Corellian Humans as examples.
Actually, it has been confirmed that the version of Lanniks in Keeping the Peace is the official version, and the version that came out two months later in Lead by Example is not. Perhaps some kind soul can link us to the place where the Devs confirmed that.
As for female Devaronians, I think that either Disney of FFG is changing their canon appearance away from the fuzzy version.
Regarding Balance within the Force.
If every Force-user sourcebook has a new Force Power AND new lightsabers, AND new fluff or crunch available for other non-Force-users, why NOT be a Force-user all of the time? I agree with the general sentiment: the Bounty Hunter sourcebook has taken FAR too long. At this point, I expect it to be the capstone of career sourcebooks. There may not be easy reciprocity between Force-user specific material and non-Force Users' stuff. This said, please stop using holocrons as plot-saving devices. The newest Force Power from the adventure was sub-par; save 'em for a wider career base choice, and please STOP naming the Force Power after its 'inventor;' else, we could have an entire "Skywalker" Force Power rulebook.
I seriously doubt the Bounty Hunter book will be the final career book out. My intuition says that it will either be the Mystic (boo
) or the Warrior. They've definitely slowed down the announcement and release rate of Edge books, but to make the Bounty Hunter book last, they'd be waiting at least two more years for Age and Force to get all their other career books out, and that doesn't make much sense.
And so far, I can't find any major imbalance between Force users and non-Force users. In fact, with a growing number of Force powers, Force users get a little weaker, because they have many more options on which to spend XP, meaning they're more likely to grow out rather than up. And the new lightsaber crystals haven't been game breaking in any way - the Varpeline crystal requires you to get and spend 2 Triumphs to get it effect, the Kimber Stone is just a bigger Training Saber, and most of the new ones have a Crit rating of 3 that doesn't decrease and little to no Vicious, which are the big selling points of the standard Ilum Crystal.