i collected two mii on the street the other day, and i'm pretty sure (from the location i picked them it didn't take 20 min.)
About pilotwings, yes the 3D is beautiful nut after a while trying to perform quick turn and himmelman to catch balloon and ring i start to see double too, but i tend to move the 3DS so i'm probably out of focus. My other game is asphalt and like ridge racer i found the same problem, the 3D is average at best when you look at the screen but when you play you tend to focus on the center screen where the road is and i don't feeel the 3D effect.
i hope for update too. for exchanging data and maybe the possibility to connect to a nintendo online account or something and upload photo there.