I'm looking forward to the grittier feel of not healing up to max after sleeping every night, especially in dungeons.
Hit dice were a missed opportunity in 5e, definitely. They should have been a reaction-based damage reduction mechanic instead of post getting hit healing. Mathematically more or less identical, but keeps you on your feet longer in the day without making you rest so much.
Patching up a serious wounds using bandages and non-magical means, still seems wonky to me though.
I do appreciate calling HP loss to be serious injury and wounds, thus restoring HP is explicitly called "treating wounds" instead of "catching your breath" as if "hit" points were "stamina" points. There's already a separate "fatigue" system here too, so that's great, a hard division of what HP means in PF2.
I like detect magic causing fatigue after a while. Terrific. I was considering picking up Eldritch Sight in 5e for a fun utility but abusing it all day long would just require the DM to line everything with lead. Every new edition of D&D (I consider Pathfinder to be basically D&D, as do many other people) has useful innovations so despite the imperfections I see here, I'm hoping some minor house rules will result in a game that runs smoother but also has some more meaningful choices to make, at char gen, level up, and in combat too.
Hero points and inspiration points are things that I will never use again. If it's not a class feature of your class, I feel like such meta-gamey rules are an affront to both realism and immersion. I like rules for non-magic-using classes to have non-magical explanations in the narrative. Hero points are Deus-Ex-Machina which is, I find, cheesy. DMs can already fudge the dice to save players, and players can already bring their fallen comrades back to life with raise dead spells and some gold (I presume). How many layers of player-side-only plot protection armor do we need?
Thankfully these elements seem minor to me, and easily houseruled, so hopefully they aren't baked in to other class abilities or feats.