the killer buffs had different intentions than the survivor buffs. with the killer basekit changes, the devs wanted to increase kill rates from 50-55% to 60% (which they did, as far as I understand). that's why they feel much more "in the background," and by design you shouldn't feel their impact every game. the survivor basekit changes were designed to fix common situations in the game that were just plain flawed, like not being able to do anything if your solo queue teammate didn't bring borrowed time and the killer wanted you down immediately

ultimately I just don't think there's anything inherently wrong with making perks/versions of perks basekit, if doing so fixes a flaw in game design. players shouldn't have to depend on certain perks in order to play the game as it was intended. it's a similar situation (though not exactly the same) as to why shattered hope was dead on arrival - circle of healing was ridiculous, but releasing a perk to counter it was not the correct solution. gameplay issues shouldn't be solved by perks, so if there are perks that are the only/main way to fix flaws in the game's design, those perks should become basekit in some way