The E-liters. They're just annoying in general, and plus, they don't fit my playstyle. I like to move around instead of staying in one place all the time. It's why I avoided the splat charger in Splatoon 1 for a while, but after trying it, it really is fun to play and is my favorite charger. I've tried the E-liter before and failed horribly, though now that I'm talking about it, I might try in Splatoon 2 (Something's different with the chargers this time, and I can't quite figure out what it is. Maybe it's only the fact that I'm using an unscoped one this time, or the motion controls. It's even better than the first game, though)
Also on the note of ink armor, I'm actually really surprised this is being said. I've faced it plenty, and I don't really find it totally game breaking and OP (though, I will agree on the tri slosher). Annoying, yes, but it can be worked around. When I used it at the beginning I actually thought it was too weak. And there's my unpopular opinion of the day (that I didn't even know was unpopular)