CHIME NOISES INTENSIFY
I never really play the post game, and here's why: After playing through the entire game, it just feels like a hassle that there are suddenly all these new places and lack-luster (for me at least) things to do if I want to complete the game. Like the battle frontier just feels repetitive and the sages thing was kind of a hassle because it was just: revisit everywhere to find one person.
Even though I said I didn't like the sages thing, I'd want to see something similar in that you revisit places you had been to in the region. I'd love if the post game was story based, and there was some reason you had to go back to previous areas for a quest or whatever where the area would have changed slightly or a lot, and you'd explore that new part to do whatever it is you had to do. (sorry my description is so vague :P) Also, I'd love if there was something like the memory link, but it was just flashbacks, and you'd meet up with characters that were somehow tied to the place you were revisiting and then there would be an awesome flashback. And that way it could be a really well developed post game since GF wouldn't have to waste their time making completely new locations! (these locations would be a little tricky to find like the hidden hollows or something) I hope at least some of that made sense :(