I spent a lot of time thinking in this video teaser.
It's complicated expect that Square announce a sequel after all frustrations that we had.
But I think that is the most obvious conclusion.
The video obviously is about something big (It's so secret I can't talk about it). And it's about an Action RPG game (Tune in to find out all about this action RPG during the show).
And this surprise have to be about Chrono Trigger (20º anniversary, Frog's Theme+sfx's).
With these 3 facts, i discard a launch to PS4 or something like that, because CT cannot be considerate a action RPG (yes, the battle system was more dinamic than others in 95, but this don't make the game an Action RPG).
So, or it is a "all-new remake", or is a sequel.
At least, i must, have and want to believe in it...