I would be surprised of that first person hadn't turned off motion control. That clunky reticle movement gave it away.
I don't have the game (apart from some testfire playtime) but I can already tell that players will benefit from learning to use the gyros as well as the sticks. You're not going to find the perfect R-stick sensitivity setting with gyros off because the stick will be doing double duty. You'll want high sensitivity to turn the camera/view quickly but you'll want LOW sensitivity so the reticle does not jump around from the slightest nudge when you're trying to aim at a small target. You can't have them both on the R-stick so you'll have to decide which of slow turning or jumpy aiming is more tolerable. The disadvantage of only using dual-analog is exacerbated by Splatoon's fast pace and 3rd person perspective.
If players learn to adjust the reticle using their wrists to manipulate the sensitive gyros while turning the view quickly with the R-stick and moving with the L-stick everything comes together. This actually requires another element of coordination which is why I believe experienced gamers often turn it off in favor of what they're accustomed to. They either want to use the R-Stick alone or the Gyros alone but can't coordinate them right away because that's trickier. It's a bit like learning to touch type after using half your fingers before. You're slower at first. Once you get how it works Splatoon's default control scheme is fluid. The key is to use the L, R-Stick and the gyros together as instinctively as you usually use the L and R together.
Nintendo provided an accessibility option for experienced gamers who're grumpy about trying controls that temporarily return them to n00b status. That's fine but remember to take off the training wheels and git gud.
