In an extended version of Dengeki PlayStation's interview with Kingdom Hearts series director Tetsuya Nomura, the question was asked of whether or not Kingdom Hearts III would also have customization as a game feature.
Tetsuya Nomura answered that it would be considered depending on the reaction towards the feature in Kingdom Hearts Birth by Sleep 0.2 -A Fragmentary Passage- as well as the consideration of whether or not they have the time to implement it.
You can find the direct quote from the interview below, with translations thanks to Catherine Mueller (firstname.lastname@example.org).
--The character decoration is the first in the series and is a novel component.
I thought that we needed something fun to play around with even in with the game's jam-packed volume, so the staff devised this at the last minute for me. It really changes the character's look, so please gather a lot of items and design your own Aqua.
--Will you use the decoration feature in [KHIII]?
We knew we could insert that feature into the game this time, but whether or not we can with [KHIII]...we have other priorities ahead of us so it depends on time, but we'll look at the reaction with [KH0.2] and consider it.
Would you like to see customization in Kingdom Hearts III? Let us know in the comments!