As I've said before, I'll be nerfing the ice elementals. However, Auric Ascended will continue to radiate ice, as he is meant to be a GOD. He can be killed by anything with the Godslayer (even a worker), as even if the godslayer unit loses Auric is killed. He's easy to kill off, and is meant to be strong.
If you meant that the unascended Auric unit is spreading ice, then we have an issue.
I haven't touched the Scions yet, is all. However, if you check some old Scion threads you'll see that I campaigned (and convinced Tarq, for a while) that Emperor should have spiritual (in addition to the rest), and I'll likely be doing that. Not sure about the Divine line getting metals, but honestly, I don't particularly like the 'new' (old now, but still, latest style) implementation for the priests. May be reverting that, in which case they don't need metals.
Alcinus will not be going away; I like him, have liked him since Tarq first came up with him as an optional addon (wasn't optional after some feedback, alot of which was mine.

).
Again, haven't gotten to all civs yet, that's a big part of what the current version is doing (and why it's taking so long); Of those you listed, only the Lanun are untouched by me.
Possible, will look at it.
I did not. Originally Chalid had Pillar of Fire and Crown of Brilliance. Kael removed Crown, left Pillar; Vehem removed Pillar (gave it to Seraphs), left Crown. I'm fine with it, he's strong enough without it.
Ice Elementals are divine magic, will stay that way. Again, will be nerfed.
Arcane is being buffed.... The Emperor will like it. Quite a bit, I think. And that's all I'll say on that subject currently.
The Scions priests are not like standard priests, their main role is to convert defeated units to Reborn.
Agree with you here. And a balance thread (so long as you realize suggestions may not be implemented, even if several people agree on it) could be a good thing.
Mazatl are getting a little bit (an actual reason to use the worldspell), and I have plans for the Cualli though it won't be in the next version. Focusing on Vanilla civs currently, and it's a mechanic that will require quite a bit of work.
Again, will be nerfed. Likely removing the ice affinity, for one, and dropping the strength.
I agree with you here, that is exactly what I've always used them for.
Again, may be reverting them to the older version of the priests. In which case, they don't need metal.