In another thread the topic of the old first editions traits came up. I started a reply, but I really felt it was separate enough from the original discussion it perhaps deserved its own thread.
I think something like this has some potential. Since 'Traits' is a name of a core mechanic used to organize feats and such, you obviously would not be able to use that name. To be honest the first thought that came up was a Gimmick, Shtick or Tweak. If these could actually be created so they are somewhat power neutral, both slight positive and negative components, they might be something that would be 'optional' choices.
If they were both positive and negative, as was suggested in the thread the thought came from, with the positive aspects no better than something like P1 traits were, you could choose to ignore them, or have a character get to pick 0-3 different ones to apply. Some could be organized with certain prerequisites. Such as some being tied to Ancestry. Maybe a Goblin Shtick that would allow a goblin with simple weapon proficiency to swap in either HorseChopper or Doglicer in exchange for losing either Maces or Spears from their simple proficiency, if that isn't over-powered getting one for losing several.
So as mentioned some could be limited to certain ancestries, and this might be a really good way to offer some extra really mundane tweaks that would be based on the person's culture. This might make some people who liked some of the optional racial traits, back in first edition. They two were giving something up to get something else.
Prerequisite: Common/Taldine language known - Reason for origin to be from a Tian region.
Replace Taldine language with Tian
_Goblin Weapon Knack_
Prerequisite: Simple weapon training; Goblin Ancestry
Choose Maces (light mace and mace) or Spears(spear and longspear). Remove the chosen weapons from simple proficiency. Pick either Dogslicer or Horsechopper, and you are considered proficient as like simple proficiency in that one weapon.(they aren't considered simple weapons however for other bonuses).
Prerequisite: Athletics Trained
Choose another use of athletics (climbing, jumping, etc). Gain +1 conditional bonus when using athletics for that purpose. Any roll for swimming, the individual is considered untrained.
Removal condition: This Tweak can be removed by a character by receiving training from a trained swimmer or having enough exposure to making swimming checks that the Player and GM agree it is dismissed. At that point both the penalty and bonus go away.
There could even be some campaign specific things, similar to the old Campaign traits. That could give a minor bonus to hit or damage to a certain gang in a town, or plus to information gathering rolls, due to some connections, or other small bonus that could be tied into a specific campaign setting. But these might even be able to be written so they can even be introduced to existing characters as they enter into a particular new adventure or adventure path. Minor enough bonuses they don't overshadow any feats, but that can help encourage some hook into the campaigns. Things explained by knowing someone in the town, or even having heard something as a fairy tail as a child that becomes relevant to a future encounter.
Prerequisite: Entering Magnimar Unleashed AP
Your parents or guardians told you fairy tales, many far fetched, but you still remember many of them. In certain encounters you may get a +1 to lore rolls to know about certain creatures. [GM Resource secret, this also offers a free re-roll on the big bad in scene 7 of episode 1 and scene 8 in episode 3 if none of the players succeed in knowledge checks]
I like backgrounds in general, and like how it slides into the character creation. However, background is limited to a singular choice, and if it is filling the spot that Campaign traits were taking, it robs the players of all the Core background choices if they are going to participate fully in an AP. If a background inspires a particular character concept in the core book, it becomes, sorry need to get rid of that and what it granted and pick one of these more limited 8 choices for this story.
I would much prefer to have some little items that are not game changers, but none the less offer a quick little tie in to the up coming campaign.
So while I don't want to discourage the option of having AP based backgrounds. I'd still love to see a smaller option that is available to tie in a PC to the story, that doesn't take up their Background slot. Items that add a bit more customization without introducing serious balance issues.
Even if it is more limited in impact, perhaps something minor, or even consumable, not unlike a Pathfinder Society Boon for instance. Rather than have it have to be something earned at the end of a adventure. Boons might be role playing tools to help integrate characters into the start of an adventure.
A GM can use a set of starter boons as options for characters to pick at the end of another adventure. Or it can simply be something truly tied to the start of the adventure.
Again, I'm not trying to say Backgrounds as an integration is bad, but I really feel there is, and should be other less singular options for it.
I'm honestly probably wishing there was something a little less than a full skill feat that could tweak a person's ability with a specific skill. Right now outside of attribute bonus, about your only choices for a particular skill is either trained, or untrained, which amounts to a difference of +3. With traits for instance, you could change a skill you had not invested in to a +1 or +2 or might be able to change a skill you'd invested 1 rank in, a +3 by being able to make it into a class skill, or boost it by one or two if it was already a class skill. This gave a bunch of options to reflect either having a particular knack for a skill, or just dabbling in one, giving several new 'level's of proficiency in 1st edition. (which after you lost some of the choices from 3.5, that traits made much easier to accept when I started playing Pathfinder and was learning its way of handling skill ranks)
In any case I hope something similar to the old Traits does make its way into the game and AP designs.