Truthfully, I would have liked a concrete mention of the new species. As I'm in the process of removing species from the USM that have gotten (or will soon get) official write-ups, knowing which ones that this upcoming sourcebook will cover would be nice, particularly as the next update will be the final one.
I wlll put my vote in for Zabraks, as I think they've been missing from the game for quite some time. Then again, that species could be one of those held in reserve for Force & Destiny, given most of the Zabraks seen on screen have been Force-users (Darth Maul and two Jedi Council masters that looked nearly identical but were two separate individuals).
Since Suns of Fortune as Corellians as a variant Human, I wonder if we'll see Mandos as a variant Human as well.
They did the same type initial post for the scout book, too. No mention, at all, initially, of any new species. The Chiss cover, many of us assumed they would be included, but just as many of us figured it was a place holder.
As we haven't seen any placeholders in this system yet (they've been pretty honest from the gate), I would set dollars to donuts that Aqualish is going to be in there. The next, more detailed, update should confirm the races.