Wasn't there a rumour recently about Nintendo announcing something Splatoon related in June? Im sure with the popularity of battle royale games that we might see a Splatoon take on it.

Not a rumor, Nintendo said in Corocoro that they will have a Splatoon announcement on June 9th. Also, you know how slow Nintendo is at adapting trends, which is a good thing in this instance. We don't need them shamelessly trying to force a rush job Battle Royal into Splatoon. 

I wouldn’t want them to rush Battle Royals but it would definitely help with the popularity of Splatoon, a LOT. And honestly it would be really fun. Especially if you had every inkling the same color, so that way you could swim through anyone’s ink. And if the map was in Inkopolis, squids could climb up the towers and buildings to get new vantage points and etc. it could be very fun. 

These are some quality stuff! Make it happen Nintendo! 

lol @ bolded, now when you shoot at an enemy you're actually making it easier for them to move around! That's an example of why BR wouldn't be good in Splatoon. You'd have to completely change Splatoon's mechanics/weapon balance/etc., to the point where it's no longer Splatoon to even get it to work. An average at best BR for $60 isn't going to take away players from the really good and free Fortnite. I'm sure we'll see that with Black Ops 4, though admittedly the game inherently lends itself better to BR so there's a chance it'll be great.

I could see some Splatoon spinoff, but I dont think we will see it this year.