I suspect that never getting a POV from a Cish is deliberate, but I'll skim through TJE and WLW to see if Meppa ever gives an indication that he is one of the Few.

In Kell and Moe's conversation when they describe each other's paths through the world, neither of them bring up Moe being one of the Few (they mention him being sent off, as a brilliant mind and interpreter of the Kipfa'aifan, to the Cish, but that's it).

Personally, I think it's not the sorcerers, but the practice, that separates them from the other Schools.

OOOO!  I've an idea.

First, the quote from TDTCB and Mallahet:

"I have come, Emperor, so you might parlay with another."
Xerius blinked.  "Who?"
For a moment, it seemed the Nail of Heaven flashed from the Cishaurim's brow.

So, no words, no glowing of the eyes or mouth (my bad).

Gnostic and anagogic sorcery are more bound to this world (through reason and metaphor), and so require the outspoken utteral as the portal through which will is made manifest. 

BUT, the Psukhe, the passion-based sorcery, requires not an utteral and an inutteral, but a conscious inutteral and a subconscious inutteral.  A perfect fusion of feeling and thought.

Perhaps, even, it is the utteral which stains the onta.

I would certainly assume that anything any worldborn man could do, Kell could do better, including imbuing another person with a direct link to a deliberate story through sorcerous means.

But I think he has enough of a grip over the beliefs of Earwa that such effort would be redundant.  Being a sorcerer-prophet - forgiving, as far as everyone knows, the sin of speaking with the God's voice - validates the gnostics beyond anything they've experienced since the First Apocalypse.

Just read through the battle at Shimeh, and it's stark how they are never referred to as singing, despite song being mentioned almost every time an SS sorcerer comes up.

Yeah, pretty sure Moe sings, glowing mouth and eyes and all, when he conjures up Skauras' face.

Holy jeepers, what if you launched the NG into the Outside via a portal?  Would that be like matter and anti-matter touching?  Would it be crushed by the sheer weight of will that seems to be the source of power and influence there?  Could it be isolated in the mundane world?

I think that, whatever the mechanism of the HS, it is a purely mundane, physical effect, and that it is still capable of being destroyed in such a manner.  That's why they didn't release it onto the battlefield until they were desperate, that's why they have a whirlwind protecting it and having it float high in the sky (I think I'm presuming that last one...).

Hell, maybe Kell's been developing cannons.  Even if they didn't have gunpowder, they could surely launch things by magical means.

I have a nerdanel that there was something in Serwe's innocence that triggered Kell's 'divine' ascendance.  She was the first to see his haloes, and Kell somehow manipulated the absolute purity of her belief and worship to expand it to other eyes, the 'truth' of her perception being adapted in the truths of other minds, establishing a firm foothold in the outside.

Didn't Proyas also read the Compendium of the First Holy War?

Kellhus is clearly setting him up to become or to do something.  Maybe some sort of sacrifice, since he has learned a lesson or two about exposing himself too honestly.