If they didn't see any value in her character, they wouldn't have put it in. As I've said before, BioWare pride themselves on their character development. They will do something with her, I am certain off it.
I think it's more complicated than that, to be honest. But I will keep my fingers crossed!
Why not? They've re-used characters from past games and shown them changing their attitudes or behaviors. I can easily see them revisiting her in an expansion or even if they move the game to Nevarra or some place north next time she could show up and be a bit more mature or they might offer us more of a chance to engage her attitudes head on.
I know they read these forums and I have to think they are already aware of her reception and the positives and negatives.
I would say it mainly boils down to how utterly disposable Sera is compared to most others. Not only is she skippable, but you can kick her out at any point in your game.
You could argue that Leliana was the same in Origins and it ultimately didn't change a thing about her importance to the series, but I'm not sure of the chances of that happening again--much less with Sera's character.
But then again, I'm just being super cynical, of course. I hope I'm wrong about all this.
Spoiler, and a personal disappointment, but the Warden apparently has had very little influence on Leliana in the end.
That's probably because the series isn't as interconnected as, say, Mass Effect was. The main thing is the Warden's influence remained relevant within DA:O, and that's what I would like to see happen with Sera. I don't even expect to see her in a hypothetical sequel to hope whatever we tell her in Inquisition will have a long-term effect on her character.