Affection in Azur Lane isn't that hard to retrain, from what I gather. it's just a hassle.
Infinitely more abusable than KC's "Shipgirls sink if you sortie with a Heavily Damaged shipgirl" mechanic. Losing affection means she'll not get any special bonuses. Sinking a shipgirl means she doesn't come home.
Then again, the old KC combat system meant that any kind of attack can (and absolutely will) sink a shipgirl in one hit if the damage roll is particularly sadistic. Just like what the Abyssals have to deal with right now. That was long before the Overkill Protection mechanic was implemented back around Operation MI.