So yes, origin stories will have more content than generic characters will. That's just the reality of videogames. They can't match the versatility of a human GM with pen and paper.
And you know completely fairly they advertised giving origins to "your" characters.
A bit of bait and switch never hurt nobody :P
Instead of say
"Origins: Play as your own generic character without one or as one of our preset characters we hand crafted."
Which honestly at this point I don't know why they don't just let you make your entire team. Given that the only PCs that have backgrounds are Pregens and they are already there in the game to be found anyway.
But I guess it would make you skip their introductions. (I really hate Sebille's... seriously... and the fact that she isn't optional if you don't want to be down a companion OUCH!)
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Actually it is funny this game, more then any others, kind of has the most companions I might have issues with...
Two are genocidal monsters... One is a sociopath... and one is normal. :P
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But honestly given that we might get more origins (especially for undead) does mean that there MAY be a point in not letting you create your team.