if not tied to background or for ex. what you were doing at the time you were abducted, would anyone be opposed to having class specific quests available for your pc? the original bg2 even had questlines where you could gain your own base by completing your class related questline or would that be too prescriptive?
Still too difficult. Ranger for example, just the favoured enemy part could indicate different past environment. Race plays another part, did you live in the Underdark or elsewhere. Natural explorer even, an urban tracker would not feel as comfortable in the forest as a beast tamer. To make a generalised quest for any of this I feel would have to be too shallow to incorporate anything worthwhile.
frankly, seeing as if feels like we have nothing in regards to a personal or customized quest at this point for custom pc outside of being part of the shared tadpole plot and despite the difficulty it may cause for a game still in ea, id take anything at this point even if it was shallow - also, the way i was envisioning a personal questline was more along the lines of the bg2 or even skyrim (altho the skyrim mechanic probly opens up some more nuance in implementation given dnd 5es class system compared to the skill trees of skyrim) as in class related questlines you could jump into regardless of other character factors, like race, background, alignment, skills, etc. - you just need that class
using an example for ranger that would largely fit regardless of the concerns cited (favored enemy, race, roleplay elements), it could be something like joining a hunting lodge or a brotherhood of wardens where you could complete assigned tasks/quests (like hunting monsters, guiding npcs, exploring fogged regions/dungeons on the map) in order to elevate your position and progress that ranger class plotline towards an end game tier encounter, outcome, and/or reward.
again just limiting these to classes there ideally would be 12 in total - one for each class, but i could also see creative ways of blurring some class lines to reduce that number (ie martial, arcane, divine, primal 4e callbacks - and maybe add skill/performance based for the rogues/bards out there) as a druid or rogue (or warlock wyll) could also likely do the above ranger example (altho thieves guild always seems to be the rogues first go to). conversely the more sneaky scout/infiltrator based rangers or shadow monks (possible opt in deity based quests anyone?) could also pursue a rogue based questline. fighter/barb could likely be combined and ranger/paladin/monk could likely even blur into those spaces too, same as the shared spaces for the primary caster classes, but i would be much more inclined for a replay if i knew i had a different possible questline tied to a different class i was running as i would be experiencing somewhat fresh content. combining that with the potential to pursue a different main story route (which is another topic of debate on the forums) along with a different race and party composition i think would make for a novel campaign each subsequent playthrough
theorycrafting just bc, so take everything at face value as i know most of this is just wishful thinking - just some real quick and generic plotlines that could be expanded on for more class specific quests, and there may be some blurred lines, but im sure and would be interested in hearing if others had more FR specific ones (ie what barb tribes are around, active local thieves guilds [i think its safe to say from ea that the harpers and zhents still dont get along], prominent wizard circles, a quest to get a candlekeep library card)
-barbarian - become a gladiator/enter into a contest of champions or you need to hunt dangerous beasts (ranger too here)
-bard - bard college (kinda generic/boring imo) or traveling circus (again, kinda worn out)
-cleric - anything related to your deity choice (which i really hope larian gives us a sh*t ton of - but diety based quests could also be a thing) but maybe something generic would be quests to help a refugee camp or combat the plague?
-druid - become a member of silvanus local grove, help rebuild it or start our own? (could be interesting roleplay for any druid shar followers out there given the history of the og bg games or any malar holdouts)
-fighter - mercenary/body guard guild, maybe join the flaming fist (or harper/zhent factions) or supporting the dukes guard
-monk - monastery or you find a fellow monk traveling on a pilgrimage but they are mortally wounded and ask you to carry their burden to a final desitnation
-paladin - anything related to your oath (or broken oath) or deity but that could be too specific, leaning on old paladin themes maybe something mount related? (if mounts are a thing that is, which i doubt) or law and order and dispensing justice for the dukes of bg?
-ranger - see above
-rogue - thieves guild (generic, i know)
-sorcerer - i think both sorcerer and wizard likely blur so closely that most concepts could work for either, but the major differences is inherent v learned arcane abilities so outside of that maybe questlines around research and magic item retrieval?
-warlock - similarly to paladins and oaths and clerics and deities, warlocks are really tied to patron choice so maybe some mechanics around that (idk if raphael is gonna factor at all here in his story elements) or an AA for folks in bad patron relationships? lol, respectfully
-wizard - see sorcerer
if your still with us reading the ramblin to the end - much love fam