SPOILERS SPOILERS SPOILERS and wild speculation
my thoughts on Davien:
Recall that Davien opposed the compact from the beginning, and that he would rather have sent humanity elsewhere from athera. (TK)
This says to me that Davien initially thought that humanity could not co-exist with the paravians, unlike the rest of the f7.
Davien also mentioned many things in PG and TK, but the phrases that stand out to me are:
1.paravian survival is paramount (to arithon)
2.you will have to choose between the compact and rathain's monarchy (to Sethvir in TK)
3.you are my fit weapon to champion the cause of humanity (to arithon)
(I Apologize for not using quote marks, wasn't sure if they were the exact words)
These things tell me that Davien is working towards breaking the compact, which is perhaps what he was trying to do with the uprising as was mentioned before by Kam. Recall that Davien opposed the compact from the beginning, and i think that in trying to break the compact with the uprising, he was trying to force the rest of the f7 to either:
1. Establish a better system of rule for humanity alongside the paravians, or
2. send humanity away from athera
Davien seems to me to be always looking to challenge his and others assumptions, which i believe is why he created the five centuries fountain and particularly kewar, challenging someone to prove him wrong. And i think that Arithon suprised him. Arithon has shown that he has the ability to rule, and now Davien changes his attitude; perhaps humanity can live alongside paravians. But he still believes the compact is flawed, particularly now when the clans are so weak.
So my conclusion is that Davien is now working towards a better system of co-existance between humanity and the paravians, perhaps by breaking up the existing compact, and is using Arithon as his 'weapon' to achieve that end.
Wild, wild Speculation:
im also going to go out on a limb here, and predict that the koriani order will fall, or be drastically changed, in SF.
but with janny you never know...
SPOILERS SPOILERS SPOILERS - and my $0.02 of speculations
I also think that Davien set things up based on having seen the future. Rather than through a scrying, I'm thinking he comes by it naturally. I'm wondering if the s'Ahelas "gift" of foresight could have been given (as in gene-splicing magically given) by Davien. And maybe Arithon's compassion came to the s'Ffalenn lineage through Asandir - hence the similar auras.)
I'm thinking that Davien saw a worse possible future than what has happened (say, the Mistwraith enslaving/devouring humans and Paravians - the destruction of Anthera), so that's why he set things into motion - much like the F7-2.5 did when trying to crown Arithon. This is the only way to ensure Paravian survival.
I think Davien initially saw humanity as intrinsically incompatible with Anthera, and later saw the problems inherent with the split society they established. I think he (correctly) believes that Arithon would replace that separation of town and clan given the chance -- as Arithon's aborted plans hoped to do. Per someone's comment in TK, the clans believe that intermarriage with townspeople will weaken the bloodline. But maybe it'd really make all humans able to safely stand in the presence of Paravians.
Lastly to the prologue, I sure hope the sages aren't on Anthera. Presumably there would be some people who would rather leave than give up their false beliefs. Maybe if the Mistwraith is removed from Marak, they could go there. (So long as they skip the advanced technology - the F7 have already seen that pitfall.)
P.S. regarding living drakes... As I recall, there was some sort of allusion to a sleeping drake under a mountain, back in one of the early books.