I definitely would've liked them to continue Street Pass in a way similar to PS Vita's "Near" feature. It is like StreetPass, but you're never required to take your system out of your house. You can exchange in-game items with people in your neighborhood without needing to meet up somewhere face-to-face.
That actually sounds really cool. I also would've liked a feature like that, since that would allow me to do Streetpass-like things without really needing to go out and never find anyone anyway. (Really, no one ever used Streetpass here)