Even if this doesn't pan out, I noticed the same connections (aka potential coincidences). Already, Sephirot's worshipers had temples that inspired Allag and eventually the builders of Qarn and so on through Belah'dia. Perhaps what survived through the ages was an amalgam of Meracydian themes. At the very least, the observations are solid Darksteelfoil Hattery, even if they end up completely unfounded.
Urianger's character keeps getting called into question, from rumors in 1.0 (started by the Circle of Knowing to distract Darnus) all the way up through meeting with the Ascian emissary (whereby he learned what he could and implied that he was a liar). Each time (so far), he's turned out to still be acting in accordance with what we've always been told he was: Louisoix's best, brightest, most loyal, and most socially awkward student.
I feel like if he was truly going to ally against Hydaelyn's best interests, it would have been earlier. He could have turned after Moenbryda's death when he met with Elidibus, he could have turned when confronted with the Gerun Oracles. He could have been more accepting of Li'lidibus (he refers to him as an ally "for now" while simultaneously speaking of the need for the Ascians to taste "lasting defeat"). What will have changed? Finally too much evidence for Elidibus' narrative? Was the loss of Minfilia the last straw? I wouldn't find it strange or unrealistic, but given his characterization (so far), I'd find it surprising. And if he did turn, I feel like he'd realize his mistake ere the end.
He's earned my trust for now, I think... I hope...
Of course, that all assumes I've not just chosen some very poor core assumptions about where the game is heading.
Predicting the big, general things - not my strongest area.
I hate to admit it, but I have voices muted for now. ARR had great choices for actors, but (imho, sadly) jarringly bad cuts of the lines. That drew me out of the game. And then all the voices changed. And that drew me out of the game. And now I can't even tell who's talking in a trailer. And if they changed between 2013 and 2015, what are the chances they'll change again? I'm afraid that just as I get comfortable with characters' identities again, bam, all voices will now be provided by Roy Dotrice.
I noticed, and then questioned myself whether that was accurate.
If other people are seeing it too, though, might as well whimsically theorize, right?
I'm reminded that Allag faced numerous rebellions on the home front and knew well the basics of summoning (hell, they invented summoners as a battle class, as far as we know). It's possible that one of the rebellions got involved with the eikon threat. However, the backstory has phrased it as "the beast tribes of Meracydia" over and over when it comes to the Warring Triad; ne'er a mention of the wandering races being involved. Could be a false lead; could bit a bit of forgotten history.
Hmm. Not much of value for such a long post.