Have just read that they've balanced the Blue Shell now. When it hits your Kart you do a backflip and wave your hands, and you keep the item you're carrying. They've also made it so that you can only hold one power up at a time, so you won't be able to have one in reserve.
I still can't believe how they've managed to pull this off on the Wii U's hardware. The Kart models look high poly and like with Super Mario 3D World everything looks so ROUND. There are plenty of high poly looking models on either side of each track, most of which are also animated. And this is all in 720p native, 60fps and with v-synch enabled. This shouldn't be possible on a GPU with 176GFlops/352GFlops [delete as applicable lol] drawing 30 Watts of power. Same goes for Super Mario 3D World and Bayonetta 2 as well.