I can see that for SH and Lae'zel, but not for, say, Wyll. Or at least it's not done in a good way. We're knee-deep in his quest 5 minutes after meeting him. As a sidenote, that also kind of hurts the couple talks where they hint he's not actually that big of a hero, or when a warlock can call him out. It's foreshadowing for its own sake, for stuff that we'll get to know within a hour's time. Again, compare with Alistair and Duncan (and Cailan!!). That's foreshadowing done well in my opinion, that on replays make you go 'oh!'.
I guess maybe it's a byproduct of the Origin's system, that we get to know a lot all at once, but meh.
It's worth to remember we don't know everything yet. They may sometimes lie or not tell us the whole truth. Or they may just not know everything about themselves. For example, I suspect Astarion isn't just a poor innocent vampire victim, and that he tells only this part of truth which makes the player feel sorry for him. It might be similar with Wyll. Maybe in the turning-point MC will discover that he is in fact a Hell's prince or something? Silly example, but I think you know what I mean. Act 1 is the exposition. We have to know origins' backstories to play with them later. It feels quite fresh to get these info in the first part of the game, because it means the writers has so interesting plans for their characters, they had to inform us about their past early.