I'm personally very fine with the companions not having a personal journey/story/quest that is tied to the main plot. Same for the PC. Because if some characters are tied to the plot in an essential way and others are not, I feel it stops being an adventure called "Baldur's Gate : Rise Of The Absolute", and it becomes "Baldur's Gate : Lae'zel Epic Adventure", say, and then you feel kind of forced to play as Lae'zel, or recruit Lae'zel as companion at the very least.
The key part above is "in an essential way". Some characters can happen to have a connection to the plot. To use BG1 as example, some companions were BG-area natives (Coran, Shar-Teel), some had come in the region to investigate the iron crisis (Jaheira and Khalid, Xzar and Montaron), some have a personal score to settle with some bad guys (Kivan, Branwen), while some are totally random (Safana, Alora).
Like you, I don't have a problem with their personalities either. Haven't seen the Patch 3, toned down versions, but I really liked everyone in Patch 2.
But I agree, some are have personal problems and backstory that are a bit too much. Well, I think I'm fine with Astarion and Wyll, and certainly with Shadowheart and Lae'zel. But Gale is completely over the top. I'm sure most GM would tell you to write a backstory for your character that doesn't involve a personal relationship with a deity or artefacts of immense power.
So, I hope the future character have a backstory and personal quest less like Gale and more like Lae'zel or Shadowheart.
