Taking the two points you addressed, I believe it has been said by the imms before the scion changes took place that it was possible for a non-mage class to lead scions. (I think it was on the farewell thread of the guy who got the Taskmaster title or something.)

If that's the case, it was incorrect assumptions by pc's who complained, and therefore was not responsible for any change. What has changed is that someone has now done it (Etarekoth). I bet up until the day he did it, most eople thought it couldn't be done.

Regarding scion purpose...

I always get the impression that the scion purpose was there in the first place, but that most scions didn't really know what it was because the "group in the know" didn't bother explaining it to them. I know when I played my pre-change scions I didn't really know.

However, I think I still wouldn't know the purpose of post-change scion had I not spent time with Ghuljun. So perhaps not that much has changed here either.