I think the logic is, for the most part, just give the character a little (or big) niche. Of course, things like All Skilled Up (giving you ability points) isn't really a niche or special skill, but I guess you could argue that character is just slightly more talented in general than other characters. Obviously they're supposed to increase your power in various ways, even Pet Pal which nets you certain rewards and hints. I don't really mind them being all over the place, but I mind that a lot of them are worthless and/or boring, and some are way too good (Glass Cannon and Bully are both ridiculous).
I would say they are quite different from the kind of feats in NWN, which tended to be small little changes or abilities that added up. They're much more like 5th edition DnD feats, which are big, unique and relatively rare. They really have a significant impact on your character. I almost wouldn't mind if they buffed a lot of the talents in D:OS a lot, and then actually reduced the number of talents you received to 5, maybe, so they'd be exciting and more impactful, though it's nice getting one every 3 levels or so instead of every 5 or 6 levels. But they should probably just stick with having 7 talents and just rebalancing them and adding more.
Part of the problem is that with 4 characters, if you want no overlap in talent choice, that's 28 talents. I'm not sure if there are even 28 talents in total.
@Dr Koin:
Random effect things are always fun, though it might be easier to tie it to alchemy or something instead of every spell or ability. So maybe like "Experimenter" or "Strange Metabolism" could give you a random effect every time you drank a potion.
Source-Crazed sounds cool too, but another task for writers who are already loaded with the origin stories. Maybe could be something more visual, like in Fallout NV, where you'd find random, bizarre scenes, and occasionally unique loot.
Here's some other ideas for talents, existing or otherwise:
Re-Enchanter/Treasure Hunter (Lucky Charm 1 or 2 required): You can reroll the stats on an item. It's value is halved. (Only problem is this basically is a workaround to to savescumming for loot, so don't know how I'd deal with that.) Maybe instead it could just let you change one stat or something, but that might be hard to implement.
Pack Mule rework: Increased carry weight + once per combat, you can use an item in your inventory (equipping something, a potion or scroll) for no AP. In D:OS EE, I'd make it reduce the cost of using inventory items in general by 1 AP, but since AP cost is vastly reduced in D:OS2, I think this kind of rework makes more sense.
Phoenix: +75% fire resist and max fire resist, -50% cold resist. Basically Zombie but for fire and ice. Might be too good though.
Inquiring Customer (Barter 3-4 required): Stores carry 5-6 more magical, rare, or legendary items.
Bloodthirsty (credit to Stabbey for this one, if I recall correctly): Gain 1 AP and a 30-50% movement bonus on a kill. Maybe some kind of downside like -20% movement speed otherwise because that's pretty strong. Also maybe can only proc once per round. Or maybe the AP and movement bonus only carries over to the next round.
I'm A Snowflake: For every unique item you have equipped, you gain 1 reputation (or more or less depending on reputation's usefulness in D:OS 2).
Personal Mage (Incompatible with Far Out Man): Spells have a max range of 5-10m, but deal 20-25% more damage and maybe have a slightly shorter cooldown (so it's also helpful for non-combat spells. I only recommend that if intelligence's effect on cooldowns is massively reduced).
Malicious Witch (Witchcraft 3): Your (witchcraft only, maybe?) debuffs last 1 more round and are 20% more likely to apply, but your spell (probably witchcraft only, again) buffs last 1 fewer rounds. (Basically Walk It Off for Witches. Since Witchcraft has only 2 buffs I believe and a bunch of debuffs, it's a bit better of a trade off than Walk It Off, though Oath of Desecration and Absorb the Elements are two of the best buffs in the game. They need serious nerfs anyway.)
Invigorating Healer (Hydrosophist 2, maybe): Your healing spells also increase the recipients movement speed by 20-30%.
Hippocratic Oath (Incompatible with Malicious Witch): Your healing spells are 30% more effective (and maybe your buffs last 1 round longer), but you deal 30% less damage.
Slow Metabolism (Incompatible with Walk It Off): Buffs and Debuffs both last 1 round longer for you. (Probably also useless like WIO, but could be fun for some people.)
