Its not a question of liking, but rather an issue of balance. Dont take it the wrong way, i respect your opinion, but in this case, this "feature" is a potential gamebreaker.
Imagine the scenario: Some mutant forgot to close the door to the masters bunker. A mosquito entered the bunker at night, and decided to have a snack. Master was critically "stinged" for 99999999 damage to the eye. A few days later the Vault Dweller arrives armed to the teeth to end the tyranny, and finds the Master dead. Game Over.
Lethal BB guns against APA MKII is just wrong. Sure, low chance, and only a few selected individuals(better criticals) could achieve kills with it, but even the slightest of chance means huge differences in RPGs. Players grind days, weeks just to get a 1% damage increase in some games. And im saying this as a current unarmed fighter not a BG, if anyone needs boost, then its HtH. But not this way. Besides aimed throwing knife to the eye blinding the opponent, knocking him out and doing 68 damage bypassing armor is quite a nice effect imo.
OR, it WOULD be plausable, if there was a "resilience" stat like in wow, that decreases chance to critically hit/decreases crit effectiveness. This way, players could at least take countermeasures against killer crits.