So I've been going over Player Core 2.
I'm a bit torn. Splitting the player book in two just so you can make more money include new stuff is a bit of a dick move. Sure, Core 1 is already over 450 pages, and slapping 1 and 2 together would result in a 780-ish page book, which is over 100 pages more than the chunky Pathfinder 1e core book and 150 more than the Pathfinder 2e core book (which both pulled double duty as the GM book). It's pretty much if they took the core book and stapled on the Advanced Player's Guide, then jumbled things around a bit to make more money.
The classes are the four missing ones from the D&D 5e roundup (Barbarian, Monk, Paladin and Sorcerer), the base 2E core Alchemist, and three taken from the APG: Investigator, Oracle and Swashbuckler. While these were also in Pathfinder 1e, I'm not a big fan of them. Oracle is a Divine sorcerer but with spooky side effects based on the source of their power, Swashbuckler is just a combo-heavy Bard who finishes you off with his sword instead of a your mom joke, and Investigator feels more like a highly specialized Rogue who gets extra mileage out of combat. And the Alchemist... eh, someone's gonna keep the legacy of the IRA alive. Core 2 is also where you find the Archetypes, a list of alternate options for all classes to give them a little bit of flavor. These range from getting animal companions or familiars for non-casters, the ability to become a healer or a leader and help your team that way, but also the stripped versions of the Arcane Archer (the 3e prestige class), but also Pathfinder 1e classes like the Cavalier (secular Paladin with a horse) and the Vigilante (fantasy Batman, who should have been a Rogue subclass from the start).
I'm not really sold on the new races ancestries either. The list is catfolk, hobgoblin, kholo (rebranded gnolls), kobolds, lizardfolk, ratfolk (the Ysoki from Starfinder), Tengu and Tripkee (rebranded gripplis). Most of these are incredibly niche, and I'm not fan of the kobold redesign. New versatile heritags are the Dhampir, Duskwalker (planar linked to the True Neutral psychopomps) and the Dragonblood, the first time you can play a dragon-like PC. The first seem like they would be better at home in some kind of horror supplement rather than a core book, but the dragon's nice. Remember, these can go onto any of the core ones, so you can have a dragonblood gnome that looks like a kobold. The last third of the book is new feats, some new magic items and other stuff, everything the Alchemist can make, a whole slew of new spells and that's it.
I fully understand why the split was done, and the place it happened also made sense for having to do a split. But this also means that to get the whole experience you need to have two books, making it twice as expensive. And if you want to lure new players over telling them that the Barbarian or the Sorcerer they want to play is not in the main book they bought is a mood killer if anything.
But with all the core stuff out now it remains to be seen what comes next. We're getting a new sourcebook next month which is going to be a revamp of the Mythic Adventures book from 1e, whcih will also have two new classes (a divine caster who can get extra spells by attuning to certain spirits, and a class that can attune to shards of divinity for a variety of bonuses). They're also revising Guns & Gears with a release in February. I wouldn't be surprised if they made a Monster Core 2 somewhere down the line, but we'll see.