There's this bit from the interview I don't get:
What scene in the trailer might they be referring to? I took a glimpse at Fancher's BR script and it opens exactly the same as the finished movie. There's an alternate title sequence in BR with visuals of waterdrops, but I see nothing like that in the BR2049 trailer.
Also, curiously, Fancher's script has voice over narration. I did not know that.
I'm just saying it's a plausible explanation. Honestly I've watched BR multiple times and it wasn't until recently that I realized Replicants weren't robots. In hindsight it's really obvious, though.
I haven't read any leaks or spoilers but the vibe I get from the trailers is that there is some kind of long-buried "secret" that concerns the status of replicants in society. Maybe humans died out long ago and everyone is a replicant, maybe replicants have secretly taken over the world and humans are the enslaved lower class, it seems to be heading in that direction.
I remember that at one time during production, Tyrell was actually a replicant and his human self was dead in a hibernation chamber that had failed. I can see Ridley returning to that idea of "would anyone notice if replicants took over?".
Passing the Voigt kampf test and appearing perfectly human would in fact be a superpower and in keeping with the kinds of things Tyrrell was trying to achieve.
Viewed through that lens Rachel's eventual failure to pass would explain why Tyrrell was pleased at the "result" because he was testing Deckard not Rachel
Let's not forget that "more human than human" is the Tyrell motto. If Deckard is a replicant then he is so human that he's just another lonely loser. He blends in perfectly with the grotty plebs on the streets. Creating a genuinely unidentifiable replicant would be of great interest to Tyrell.