EDIT: Checking the trailer, the Splatoon players pick up a Pro controller before playing. Either they added a boring old dual analog scheme to appease complainers, or that confirms that gyro controls are in for the Pro. Hard to tell.. the camera movement looks like analog stick jerkiness, but no one is ever using the right analog when the controller is shown.
https://youtu.be/f5uik5fgIaI?t=2m45s
Really disappointed by staggered sticks... the upper right stick was really comfortable to use on the Wii U Pro. If it actually has gyro controls this time that will make up for it... if not, I worry about whether there will be a decent way to control this system. I'm not really interested in a 360 pad clone (Splatoon would suck without gyro), and I don't think the default controller looks comfortable to use at all... that D pad seems like junk. The rumors of a split Sony style D pad would have been much better than this.
Has it even been confirmed whether the joy-con controllers have full motion? It looked like someone was slashing Skyward Sword style at one point in the video. It would be really cool to have that back- like a fully wireless Wiimote+nunchuck but with a right analog and fully conventional button array. Losing the IR camera is a big setback, though.
REALLY hoping each joy-con has WM+ motion-sensing hardware. I feel like that would go a looong way towards recapturing some of the multiplayer success they found with wii sports. How much does a gyro+accelerometer (or whatever they're using nowadays) cost? Surely it can't be that much. Pretty sure the wiimote's accelerometer was below $10 in 2006.
Probably not much, but without the IR camera + sensor bar to calibrate it would definitely need a magnetometer, and even then it still wouldn't work particularly well for shooters (Move didn't). At least, not in the same way the Wiimote did.