To be honest I think Nintendo is targetting the hardcore market with the 3DS. However they are trying to maintain the casual market they built. I think 3DS is both a hardcore machine and casual.As I told Gilgamesh on the Sony board sparking this thread.
I think in the end the 3DS is no less hardcore then NGP, nor is it any less casual then its prediscessor DS. Nintendo is merging hardcore and casual markets into a device that has content for both types of gamers. I think the software speaks for itself the Nintendo 3DS is definatly hardcore, but it also shows that it is casual.
Things aren't always black and white (Casual or Hardcore). On a side note I think this poll proves my point that the VGChartz community really does consider the 3DS a hardcore machine, while they also consider it casual. Which is inline with what Nintendo is doing.