It depends on why they have a low tick rate in the first place. If they did it to save battery and make things work better when people are tethered to a mobile connection, then it would be as hard as dealing with the fallout when battery life drops and suddenly people can't play it reliably on the go (or slurp right through their data plan on the go).
I think that it is a "what is the Switch?" issue more than it is an issue with the bits on the disk, in other words. Is it more important that you can play on the train, or more important that you can rely on your reflexes to save you when you're caught out in the open in game?
If they also got dedicated servers (which feels like a pipe dream with Nintendo, admittedly), they could quadruple the tick rate and still be using little more than half the bandwidth as they are now, since each Switch would only be sending data to one server instead of 7 other Switches. It's very much possible to accomplish both goals at once, but Nintendo doesn't seem to see it as profitable to do so.
I dunno, I saw the video last page but for all we know this affects one in a million matches. I've hidden behind walls from snipers and been safe. I've gotten shot by snipers and it's been a totally legit hit.
I'm not sure to what extent this is something that could actually be exploited RE: "less skilled players getting cheap wins." Like...take shots you know you probably can't hit because you might hit them anyway due to the rate?
There are some competitive games where certain playstyles are less effective or minimized...if Splatoon 2 puts evasive or defensive players at a disadvantage (which I haven't really seen thus far, my main playstyle is to be relentlessly squirrely), then that's just a fact of the game. Competitive players will be aggressive because that's how you have to play it.
This affects every match to some degree. You don't seem to understand how this works, though. If you're shot from behind a wall by a sniper just after ducking behind it, it's not like the sniper shot at the ground where you were or something; on his screen, you weren't behind the wall when he took the shot. I've definitely seen my fair share of this (and probably dished out my fair share as well, not that I'd ever have a way of knowing). If you try to hide behind the wall at the last second, it just doesn't work half the time. It's particularly frustrating as a charger main, since I know the timing of the charge so well. In a sniping duel, I'll try to time it out so I'm always behind a wall when the other charger is charged, just to get shot through it anyway.