As I said "Sure, there might be the rare few god-like aero players but thats doesn't mean the weapon is competitively viable as a hard threat to other weapons."
I am not talking about the player, I'm talking about the weapon. Someone who can get to S+99 with aerospray means they are a very skilled player. There is nothing inherent to using areospray that lets them get any easy kills or an advantage other than the inkzooka and the video proved it. All non zooka kills he strafed and juked the crap out of those players in their own ink, that's why he is a good player, not because he was using an aerospray. He could have been using any gun in that quick shooter class and pulled off those jukes and likely wouldn't have to work as hard to do it.
And that's why we have a crap meta where there's a few viable weapons, and the others are junk, hopefully this will change a bit with 2.20, but that way of thinking is ruining the meta, you must play what you like, not what you think is god tier because other players say, what happened on Inkstorm? Omohide(Memories) won playing what they like, not what meta said, meta in Japan before 2.20 was
"S+ (nearly necessary for a team)
Tentatek Splattershot/Octoshot Replica
.96 Gal Deco
E-liter 3K and variants
S
.52 Gal
Krak-On Splat Roller
Blaster Custom
A (occasionally viable)
Luna Blaster
Splattershot Jr.
Dynamo Roller
and clearly, Inkzooka, Kraken, and Splash Wall are the essential factors of competitive matches."
On most matches BS used 3K, .96, .52 and the octoshot, three S+ tier and one S tier.
While MM used Luna blaster, Range Blaster, Dynamo and a 3K, we'll say Range Blaster is A tier for now, so we have three A tier and one S+ tier.
What is remarkable is that the one with the Luna Blaster is usually the center of the game, because of his style, really aggressive and he moves a lot, if you watch the videos of the grand final you will see that Omohide has a more stable game, and they had the win in their hands since the begin, I think because they use the weapons they like and then make strategies to make that setup work, indeed they have some S+ weapons like walls and the inkzooka, but they prove that question here is how you master the weapon, more than what weapon you use, that's why I say it's viable, if a player likes that weapon and want to use it on tournaments and rankeds he can do it, just because it doesn't appear on S and S+ tier weapon list automatically you have to discard that weapon.
The whole inkstorm shown that Japanese teams has one or two weapons per player and they usually play with the one they like more, no matter map, mode and opponent setup, they build strategies with the setup they have, not based on the tier list like an unbreakable rule.
Also you said we're not talking about the player, but I think that our target is to build ourselves as good players, do you think it really matters what weapons we use if we don't build ourselves as good players? I think the viability of any weapon rely directly to the players. As musician is like If I think I'll be an awesome musician because I invest more money on instruments and setup than time on mastering the skills needed.
If people like that weapon, they just have to take it, they have the prove that S+ 99 is possible with that weapon if you train enough.
Also I'd like to say as a Dual Squelcher main, when I got to S and didn't saw any of them I nearly dropped the weapon, I nearly took the .96 gal, and finally I dropped the idea because until that point I didn't have to change the weapon to be the top layers a lot of times, to deal with splash walls, or inkzookas and dynamos, and then after few weeks other Dual Squelcher on S+ showed in my games, and got top player, proving is the skill of the player that matters.
Just because someone can make something work, does not in anyway mean that it's truly viable. If I'm the greatest Splatoon player alive, I can make the inkbrush look god tier vs people who are inferior players to me. To me, it it just shows the Japanese player's much higher skill level than all of the players he encountered. His skill greatly made up for the weapon match ups.
I know a couple of Inkbrush main players and they can kick the *** of any weapon, as I wrote before, we must build the skill based on what we like if we invest enough it'll pay off, the meta is just a reference.
What makes a weapon viable is you.