Say what you will but Echolocator is a great balancer in this game. Prevents ninja squids from ripping through absolutely everyone. It not only helps the 3k litre pin down foes, it can work in reverse, alerting the rollers and shooters to the potential locations of chargers and take a more cautious approach to advancing.
NS (ninja squid) comes with a 15% speed reduction. It takes the equivalent of 2 mains of swim speed up just to return to normal speed (which is already kind of slow). And as much as i like NS, the usefulness of stealth swim is still rather situational since in most cases there will be blobs of enemy ink in your way of the opponent. It would be a niche ability even if there were no echolocators in the game since most players would be put off by the brutal speed reduction of NS, the limited usefulness of stealth swim in general and would simply rather have the advantages of other abilities instead. And as a testament to its limitations observe how players using NS aren't "ripping through absolutely everyone" in matches where there aren't any echolocators being used. You will see that NS is not overpowered at all. Echolocators are fair in most cases, but it can absolutely destroy the meta-game for some very short-range weapons (most notably brushes) not using CB in top competitive gameplay. For some weapons, you either have to kill yourself or run & hide for 14 seconds. At least with other specials you have a chance to outplay your opponent. This is why i wish CB (Cold Blooded) was available to other types of gear since echolocator spam makes ninja squid, recon, and haunt not optional for those few weapons that need CB to be tournament viable.
That's probably why they have it set up like that though. So that an inkling can't be essentially invisible for an entire match.
If you think NS makes you invisible for an entire match then i don't think you've ever used it. You're only invisible when swimming. More often than not if an opponent has seen you then they know your position will be limited to the body of ink you're swimming in and will start shooting at your body of ink until they hit you - which is often what they'll do regardless if you're using NS or not since visible swim streams can often be hard to trace. Also, lets not forget the enormous speed reduction of NS. If that's not a fair trade-off, I don't know what is.
I do this with other builds that I use, but often the mobility is much slower than NS with maxed out swim speed. If I felt it truly achieved the same effect as my NS/Swim Speed build then I probably would've dropped NS by now.
But earlier you made it sound like eccholocators WERE getting spammed left and right. From my own personal experience, that is definitely the case. As a Dual Squelcher main, I add to the chaos but I've seen a great many Elitres, Zap 85s and Dynamos doing the same thing.
They're not getting spammed left and right in every match, but there are some matches where they are. E-liter 3K and Dynamos are 2 of the most popular weapons so getting echolocated is not uncommon at all. It is a popular special weapon and highly effective, but they're not being used solely to counter ninja squids since most players don't use that ability.
Same could be said about Cold Blooded. But with it, along with echolocators, getting nerfed, it probably won't be overcentralized as Ninja Squid and Ink Resistance once were. The game is almost balanced with this next patch. If only Sm4sh was making this kind of progress.
