The only important ways I felt it was misleading is the the solution to the primordial light was the blessing of light and "become what you must."
I did NOT expect a side change or an evil Hydaelyn. I did expect a better rationale for the Ascians than what we got, which essentially boiled down to "runaway chasing of sunk costs" and buyers' remorse for saving the world (hey, Zodiark? Ya know how we sacrificed 3/4ths of our population to make you and restore life to the planet? Can we get take-backsies on that?).
I would have liked needing to use some fragment of a dark power to overcome the primordial light. I would have liked it if Vauthry's regime wasn't Lahabrea levels of obviously evil.
The resulting story was one of the best in FF14, maybe post PS1 FF in general. It had clear themes and knew where it was going, unlike Stormblood. But it wasn't what was advertised before ads with major story details dropped (and we were told that the Blessing of Light was key).
"Become what you must" especially puzzles me as a tagline, because not once do we make a choice our avatar seems uncomfortable with. I also agree that the Master Matoya bit seems a deliberate red herring.
