Speaking of difficult Japanese in 3DS games, I have always found the Bravely games to use much more advanced Japanese than any other RPG.
I've played the first two Ace Attorney games in Japanese, and they weren't as hard as I thought they would be.
well... daigyakuten saiban seems quite challenging at times... didn't try the older AAs though.
but yeah, I noticed that too while playing the bravely second demo. Not something I'd play before bedtime... It seemed pretty demanding, and that was only the demo.