Splatoon's latest major adjustments are going to upset a lot of players, but they were changes that needed to be made. Rollers take the biggest hit, with splash damage only being able to one-shot players that get hit with the center of the roller, and having their damage altered when repeatedly swung.
Blasters also suffered at the hands of the dreaded nerf bat: Maximum AoE damage was reduced by 36% (from 125.0 to 80.0). On top of that, even with Attack up gear augments, the AoE damage is hard capped at 100.0 damage. R.I.P Blaster-user's rankings.
The mighty Kraken was hit as well, but the changes aren't quite as significant. Filling the special gauge now requires 200 points of covered turf as opposed to 180 points, but since you're likely to st on a Kraken charge until necessary, this change isn't that big of a deal. The size of the hit box to push the Kraken back has been altered, and users will have to wait 0.75 seconds after triggering the Kraken before they can splat opponents, giving them a split second to react and flee for safety.
There are a slew of other weapon changes detailed, like nerfing my precious splat walls, but not all were decreases. There were also changes to Splat Zones, Tower Control, matchmaking, and ranking calculations. For a comprehensive list of changes, take a look here.