I knew going in to expect the Leviathan fight to be different from what we saw in E3 2013, but I was really surprised to see how much they managed to keep. I thought for sure the water-Leviathans were goners, so it was great to see them again... especially since I actually like the transparent mini-Leviathans more than the indistinct foam from the E3 2013 trailer!
The QTE stuff was utter madness, as expected, but the real star was the massive, warp point heavy battlefield for the actual fight. I imagine that fighting well will require one to warp all over the place, which should look and feel awesome. And then Super Noct showed up, and my jaw dropped. I hope we get to take advantage of that mode at least a few times throughout the game.
With that said, I really have to wonder when this footage was recorded, given that the block icons didn't show up properly during the QTEs. >_>; If that footage was from an earlier build... >.>
They're also basically just cues to use an existing part of your moveset when you might not necessarily be expecting it. But I guess QTEs have been misused enough elsewhere that simply having the cue pop up instantly draws unwanted comparisons. =P
(I wonder whether you can turn the block prompts off without removing the entire UI, and if that will affect the more cutscene-y stuff.)
Noct has weapons instead of elements, but the spherical defensive aspect of his powers and the fact that they're inherited from his predecessors both seem more Avatar State-like than Super Saiyan-esque.