i wonder...

[Jowy]

Good frontsite content if we can get some solid proof.

What treasures turn into other items if you wait until further in the game to open them up? Off the top of my head I can only think of the Rune Edge in the Moogle's Cave eventually turning into the Drainer, and whatever the hell in the cave to South Figaro that turns into a Thunder Rod and eventually a Ribbon if you don't open it until the World of Ruin.

Anything else come to mind?

[*Laurelindo*]

The chests that you pass with Terra in Narshe at the beginning of the game change as well, in WoR; I believe they turn into Pod Bracelet and Elixir.

Oh, and I believe the Rune Edge actually upgrades into a Ribbon in WoR.

[Spooniest]

The swag on the outdoor sections of South Figaro also upgrades in the WoR, though an itemized list is kind of beyond me at this point.

[dandy da oak]

You guys just need to click this (http://www.gamefaqs.com/gba/930370-final-fantasy-vi-advance/faqs/47026) guide and do the CRTL+F search for "->" to see all the items that change ^.^