Assuming Nintendo knows the competitive metagame at this point (they have always seemed to, for the most part), I could maybe see Stealth Jump being removed. I'm not really sure if it needs to be, but it's very possible.
A big problem with Stealth Jump was that they balanced it incorrectly. If you remember, a long long time ago, the designers "nerfed" SJ so that the jump was much slower than it originally made a super jump at launch. However, that's not the way they should've done it. You know how everyone says the way to counter stealth jump is to watch the sky so you can see the guy jumping in, then you just pop 'em? Well it just so happens that you WANT the slower jump for that reason: if you take longer to jump in without being detectable by regular means, the person you're jumping to has more time to spread out so when they die, you're not being expected in that very area. You're going to be in a completely different place, and the opponent is going to lose track of you because you didn't jump to a predictable place. Therefore, you don't really need QR to break SJ; it's still very powerful on its own.
That said, it's a great tool for keeping momentum. If you're winning, for example, and you're defending in Splat Zones or pushing in Rainmaker, you can get back in extremely safely and the other team doesn't really have time to focus on you - they have to concentrate on the objective because if they don't, they're going to lose. Stealth Jump lets things like Tentateks, Lunas, Dynamos, you name it, keep the pressure on such that they're even harder to stop than they were before, because not only do they now have some element of surprise added to their approach to crucial areas of a map, but they also have a way of coming back in safely and doing what they do best from there.
I don't know what Splatoon 2's match pace is going to be like, but I think with how fast the game is at this point, Stealth Jump adds to the speed, but at the same time you can argue that we need safe jumps to get back in quickly. The Japanese community actually uses SJ largely as a way of preventing lockouts, which I assume is because they have safe jumps back into areas that may otherwise be taken quickly if a player were to instead swim there from spawn. So in a sense, it helps you fight speed and momentum with speed and safe plays.
Also, I feel like people always jump to the argument of QR/SJ being amazing for trades, making your death irrelevant, without thinking about the significance of the trade given the situation. Trades mean different things for a team, depending on whether they're playing the neutral game, offense, or defense. In neutral, trades normally don't mean too much, but w/ QR/SJ, yes, the trade basically never happened and your death was irrelevant. But you need to look beyond that, because trades are much different in the other two cases I mentioned. They don't impact the defending team as much as the offending team, because the offending team loses one more person who needs to push/go out and fight, whereas if the defense loses a guy, they have other people staying back, sharking, covering angles, etc. This means that a defending player with QR/SJ is doing nothing with its abilities, while attacking players with QR/SJ can make use of their faster respawn times and safe jumps.
I'm sort of shifting focus back to problems here, but I think they shouldn't have made it a shoe ability. And I'm surprised nobody has brought this up. I feel like the fact that it's a shoe ability makes it that much more elusive, and people feel like they're getting screwed over by something they weren't expecting. I mean, let's be honest here: you have, I don't know, roughly 2 seconds per team to see what every player on a team is using/wearing. That's not a lot of time to take in everything the other team has on them; you may see what at least one or two people are wearing and/or using as a weapon, but you won't catch everything. Plus the shoes on an inkling are the hardest gear pieces to visually see, since 1) they're small as hell, and 2) the spawn-in positions were done wrong, so you're probably going to miss certain information on a character in the back, on the left, or on the right. I really think if anything, it should've been a headgear ability so that you could look at a guy and immediately say "That guy's using SJ, Imma 'bully him' for it". I know
@CM2 essentially brought up the idea that seeing the other team's weapons will give you an idea of who's running SJ in the next game, but this isn't necessarily true. Specifically in solo queue, everybody runs different sets, whether those sets are built or haphazard. And more to that point, you can't generalize every weapon into a QR/SJ category. It's easy to predict it on Luna Neo, but things like Tentatek and Dynamo (also prominent QRSJ users) have plenty of different builds. For example, some Tentateks run speed builds or defense/damage builds, and some Dynamos run Damage Up builds. You could even run efficiency builds on Dynamo. They have plenty of options, and as such you couldn't just look at a weapon at the top of the screen and say "oh he's using that" because just that's not how it works.
That's really it from me. Also, why are people saying Stealth Jump + Splash Down is going to be broken? Assuming they keep the "you can't attack during a stealth jump" part of it, you won't be able to use the special anyway.
when I have other things to worry about like map control and the location of our enemies. It's also far too abusive with 
