Did you ever play FFX? The halfway point for the script is at the Moonflow. The general consensus is that the halfway point for gameplay is at or right after Macalania Temple.
Same deal here. Dungeons will start to get dramatically longer from here on out, as well as having a scene scattered here and there rather than a bunch of back to back movie segments with a room or two in between. There's still a bunch of story stuff right after you finish or arrive at a new place in the story, but well. Don't want to spoil it.