I've thought for a bit... and, something came to me: can we truly get rid of the Scions without killing or stranding them?

As far as the WoL goes, the Scions are the most resourceful allies they have... If you want an authority of knowledge, why wouldn't you ask for Y'shtola, Urianger or Krile's help? Same for a trustyworthy tank, or someone with diplomatic influence. Not saying that new characters can't assume such roles, but if you do already have those contacts - close people that you can fully trust - why not?

I'm not putting this as a 'want or want not' for them, but maybe a realistic situation to think about. Even if Dawntrail didn't feature any Scions at first, or just one or two, we would certainly see them coming in as soon as the 'good vibes' plot gets deeper and darker with the evolution of the new arc and the specialized help is needed.