I'm definitely going to capitulate here and give it up to anyone who is expert in a field that I am not...say like graphic art. You say two dimensional bows can only have so many varieties, and I will concede.
That being said, I'm pretty good with plot devices. Dialogue and codex choices were designed to make us curious about Sera's connection to the fade, old gods, etc could be a red herring (intentionally laid out by the designers) or it could be a portent ("yet i hope they do not point to me"--paraphraise Shakespeare when Desdemonia is about to bite it).
Blower's writers are pretty consistent across the series. They had to have planned some of the information out in advance.
If you are going to hire voice-over actors and bother to write and direct them (BTW good casting on whoever you cast Bioware), the undercurrent of Cole's voices dialogue becomes more important.
The breadcrumbs that point to Sera being different (or boringly ironic) kind of hit you over the head.
I concur, the whole thing could be a giant red herring, but Bioware introduced it into dialogue, so even people like me who tend not to read the codex's have to start wondering...what is he talking about?
Did I come up with the theory? Nope, I'm not that bright, but it was heavy handed enough that even I was like...what's up with Sera...a google later...eh, yeah, I can buy into the possibility.
It's really kind of fun since the cannon is in constant motion. What is catering to a fan base? What makes a good game? How can we sell this product to everyone and make most happy?
As fans if we think we "figured" something out and Bioware is like...yeah...we planned that, but no more...they can redact what we've never seen.
It's entirely possible they don't care too much about what we think, because we do all their advertising for them.
Hey I write fanfiction...there's no money in it...and before fanficition I never wrote a word without a paycheck.
We eat it up. We love/hate it. We advertise it. We think on it, but in the end...
Who leads the story? The fans? Bioware? Or do they look to us and go...hey that's pretty good idea. We should borrow that idea from fan X overthere. I know if I were a story editor, I would.
Fans can never write what Bioware can. They write the cannon, and can make revelations in the story. We can't. We can just make our peers think.
Isn't that what makes the whole formula kinda fun?