I'm expecting some manner of twist rather than a one note and rather predictable path for the story to take. Which would be very much in line with Shadowbringers and Stormblood in terms of the story elements that were revealed. I'm not even convinced that either Hydaelyn or Zodiark will be given much focus as anything other than convenient plot devices...and in the event that do get more focus, I'm inclined to think that it'll be in the form of a story resolution that works for different groups of players rather than just one 'side'.
More importantly, though, the full trailer isn't even out yet, nor is the second half of 5.5's MSQ's. I don't think anyone can be certain of anything at this point in time.
It's odd to me that there's so much weight given to traditional JRPG tropes and themes of 'heroism' around these parts and yet one of the biggest - the 'benevolent' deity turning out to be sinister/manipulative is mysteriously a big no go. Personally I think it'd be an excellent way to show that blind faith is a bad thing (as we saw with Ishgard, Garlemald and countless other aspects of the game world). Though I suppose we can all agree to disagree on that front.