I'm actually pretty fine with it.
First I had to scream at the screen because I thought they killed my bitch husbando, but turns out it's all a ploy to force Alisaie character growth. She's best girl anyway, so nbd. Soul calling is definitely an anime trope, but we can't pretend like the story hasn't been moving towards this all along: a select few groups "know" that the balance between light and darkness has to be kept in check - this is what we've been told by the Ascians, anyway - and one of those groups is now screwing with possibly the only group of people in the world who can meaningfully affect events, trying to get them to choose balance instead of too much light. It'll be interesting to see who it is. My guess is aliens from the moon :D
As for Garlemald being Ascians...well, it's always Ascians, isn't it? (Except for that one time it was our mirrorworld doppelgangers). I assume the game's main plot will essentially end with another calamity being brought down, partly by our erroneous actions so we come full circle from 1.0, Deus ex Hydaleyn saving our asses and leaving our world to its own devices so she can't poison it with light or whatever, a bunch of characters dying nobly (my money's on Thancred and Alphinaud because all my favorite characters always die and one twin always has to die), WoL and friends dissolving Garlemald post-crisis and kicking out the Ascians forever. Oops, I made up my own anime ending.
Beating down the Steppe tribes is what they wanted in exchange for their loyalty and manpower (they've all got a few screws loose from too many axe hits to the head). Not a bad deal, really.
...I like playing story characters in battles, but the implementation is pretty bad. You're telling me all Y'shtola can do is 4 spells? Please. I suspected people who avoid playing healers because they don't like it would hate that part, though.
Anyway, Ascians are pretty heavy-handed overall and I'm not a big fan of them and their evil mastermind shit either. Story would actually be much better if it was Game of Thrones-style head-bashing, kingslaying and espionage and none of this Scooby Doo Ascian unmasking as the main plot twist every expansion...but it's far too late for that now, so they're all in with the "everything was Ascians all along!"