Some.. interesting 6.4 trailer tidbits... (with no context):
One of the nations of the Thirteenth before the Flood was the Kingdom of Baron (continuing the FFIV references) - so does that make that blonde guy briefly seen Cecil? (Doesn't look like him though)
The Cradle of Darkness seems to be used to make a giant voidgate to the Thirteenth which is how Golbez's trial is accessed (fitting)
Themis seen in the Aitiascope (thus blowing away my theory that the Pandaemonium that appeared in the Lifestream has been there all along)
Remix of Amaurot's theme 'Neath Dark Waters/Mortal Instants heard (the Aetherfont's dungeon theme?), as well as a remix of Main Theme of FFIV
More stuff as well but that's what stuck out to me.