The Splatoon franchise is the best shooter franchise ever made.
The most pro-consumer business model. The most content. The best core mechanics. The best lore.
Even if you hate the Splatoon music vocals, at least the games bother to have hundreds of original songs, most of which varied and unique. The average match in other shootees is silence with gun noises and voice lines.
To be clear for those who have never played, Turf War is NOT the only or even main mode of Splatoon.
Splat Zones is like King of the Hill, Tower Control is like Overwatch's payload, Rainmaker is somewhat like Capture the Flag and Clam Blitz is the most complex mode, being somewhat like American Football, but not really at all.
Nintendo cares about the competitive scene, it gets tons of updates and there are so many unique ideas to it. An actual hub world, shopkeepers on real world timers to buy clothes (with in-game money, no microtransactions), having builds somewhat like Pokemon EVs but you pick the stats. Etc. etc.
One underrated thing is how short the matches are. Because it's a fast movement shooter, the Ranked Modes are all 5 minute matches with overtime (which usually can only last about thirty seconds). While Overwatch for instance has early knockouts at timers, Splatoon has knockouts that can happen in 45-60 seconds, and the maximum time really respects the player's time.
Another interesting thing is that all maps are symmetrical at an angle. This means both teams have the same spawn essentially, which is extremely unique for the genre, and reduces a lot of headaches with spawns.
I mentioned Overwatch's payload but that mode only accounts for one team being the attacker. In Splatoon it's much more fluid, whoever is holding it is holding it. Both teams have a score in every mode, and instead of the objective being defense or offense, both teams have the same objective.
The games chaotically swing with you getting a wipe on the other team and frantically moving to offensive positioning, painting as much as you can to get your special (ult) and keep the opposing team out.
So much more engaging, in my opinion.
Are the games flawed? Yes, even some really really weird decisions. But also, that's all PVP games? To have such a quality shooter with so little to complain about that the main controversy in the community isn't "$20 skins", "No content in years", "The Company literally destroyed this thing"
it's just
"We are only getting 2 new PVP maps, 8 new kits 2 new main weapons, three new songs, several new LTMs, a new PVE map, balance update in 3 months, new cosmetic features and a few too little new clothing options. That's too little content!" (for free, by the way)
... then yeah, I think it's at minimum a contender.