Legacy Character Intro

[Enkidoh]

Yes there is a requirement to get the 'Legacy' opening - SE confirmed this not long after ARR was launched (found here), and it was entirely based on exactly how far you got into the original storyline of version 1.0 - namely, you had to have passed the Lunar Transmitter battle in Castrum Novum as a part of the Seventh Umbral Era storyline.

If you accomplished this requirement in version 1.0, then when you transferred your character into ARR, you would start the game with a slightly different opening of your character teleporting into Eorzea at the Althyk Deity Stone in Snakemolt (like in the 'A New Beginning' trailer), and would have slightly different dialogue throughout the game in certain story scenes, as stated officially by SE below:

Greetings,

Please rest assured that this is in fact not a bug. In order for the alternative opening cutscene to play, you had to have cleared the Castrum Novum quest in 1.0. If this requirement was not fulfilled before the final data save, this opening will not be viewable.

I apologize for the delay in answering the questions and concerns about this, but if this was holding you up from progressing, please know that it is safe to do so. We hope you enjoy the story!

If you didn't satisfy this requirement, the opening you get is the same as that for a new character or player, regardless of what you accomplished in version 1.0 sadly.