Like Splatoon 1, gyro aiming clicked pretty easily for me. Sure, Y axis stick aiming would be nice as well, but I really don't have any problem with its absence. Though I guess it helps that I generally avoid console shooters like the plague because twin-stick aiming is a garbage fire.
Still not as good as the Steam Controller implementation (trackpads+gyro) or M&KB, but gyro-supplemented controls are frankly the most tolerable way to experience a console shooter as of yet, for me. It's baffling that PS4 games simply don't use that functionality.