Heroes of Ruin was always a built-from-the-ground-up 3DS game

A portion of a NintendoGal interview with n-Space's Tim Schwalk...

NG: Was this a game originally planned for the Nintendo 3DS?

TS: Completely. Heroes of Ruin has been built from the ground up for the Nintendo 3DS. From StreetPass to SpotPass, we’re utilizing nearly every feature of the hardware, including internet multiplayer with voice chat.

Full interview here