Don't know, but some "special characters" from other SE games would have been great as well, I think.
Maybe SORA (ohhh surprise), some Dragon Quest or Valkyrie Profile characters.

Or at least just as I Don't Need A Name said, more (interesting) characters but not only the mains.

I also didn't like the american voiceover, so it also would have been great if they had given the player the choice to choose between either Japanese or English voices.