Also, how is it a gimmick?
Remember how everyone was so psyched about the Wii because they were so amazed by the motion controls? The motion controls were pretty much the only thing the Wii had going for it. Other than that, it was just a white GameCube that was a bit slimmer.
Think of that 3D bullstuff on the 3DS as the motion controls of the Wii. Once you get past the 3D stuff, you realize it's pretty much the same old bullstuff.