Seriously, it is just a 'Wi-Fi'. I don't see any problems with it. Beside, if they have 'Wi-Fi' function, the game will lag easily. I'm happy already that Kingdom Hearts already has 'Multi-player mode'. And you can play all main characters in this game, exclude Namine and Kairi. 19 characters + Events + Multi-player + Worlds + High quality cutscenes are already many. Basically, a PS2 graphic for Nintendo DS is really hard to make it. And Square Enix eventually did it (Or maybe it has the best .dpg video format...) You can't expect more for a Nintendo DS game. But you can expect that on a PSP game.
Be happy that you can play 29 characters and have PS2 graphic/best .dpg video format for Kingdom Hearts 358/2 Days. Even if you complain, mad, hate or blame it, you can't change everything, right? And as someone said, Days reached the limit. If you're keeping complain it, then why don't you do a Kingdom Hearts 358/2 Days with a Wi-Fi function? If you did that, then you can complain what you want and see us as idiots. I doubt you'll make it. Or if you really blame that this game doesn't have Wi-Fi function, leave this game alone. Don't ever play it. That's the best solution. And you're not acting childish, but wildness or barbarism. What you will comment on me, I don't care. Because I know you're just acting barbarism.
And I don't piss on this game. I love it so much. I would have to say, Well done! Nomura! You've made the best Nintendo DS game.