One thing the game doesn't immediately tell you is that you don't actually have to be confined to the twitchy motion controls, and there's actually an option for touch controls in the settings. You'll have to go to the main menu to find this option hidden away. After activating, you'll be able to steer your snowboard with your left thumb. It's still a bit twitchy, and this will be a matter of preference rather than a universal rule, but many players are likely to prefer this method of play.