Honestly, I think they were very eager to nerf inkjet. Sure maybe one or two nerfs to the splash damage/coverage would have been fair. But, the genius people at the squid research lab decide to put an enlarged hit box (because it was too hard to aim with my splattershot), and they nerfed the exhaust damage to the point where you can't scratch your opponent anymore with it (which is pretty dumb tbh).
With all that in mind, I have no idea why the ttek's special charge got nerfed. The weapon doesn't need inkjet to be good, it's the splattershot, one of the easiest weapons to use in the game. Notice how in splat 1, the tentatek dominated with it's great combat skills and movement options. Heck, most tteks in the last 3 months of the game just ran quick respawn and died, so they never got their special. It didn't matter as long as they had the good base weapon and a bomb as a sub. And nerfing it at this point would be mass chaos, because it's what half of the community mains. It's even on the amiibos, even the amiibos main the ttek.
All silliness aside, it really would have been interesting to see how the splashdown, baller, and stingray buffs would have looked like with ink armor and inkjet untouched. Ink armor needed a nerf, just because every team ran at least two ink armor users, but inkjet could have been untouched for a month or two before we really cut down to the chase.