Well they would have had to completely write new code to program in the wireless (of any sort) multiplayer, not to mention it would be a pretty huge addition and I'm not sure how much space is left on the DS card for that sort of thing. Abyss is a pretty big game, all things considered. :x Maybe there just wasn't room? *has no idea*
Wish they could've gathered the English cast back for it to record skits. ;_; That would have made it a day 1 buy and I would have a 3DS right now in preparation for it.