Mobs should run if another mob has died

I feel like mobs are way too chill when one of their buddies gets wrecked. Like, you take out a zombie and the rest just keep walking toward you like nothing happened. Shouldn’t they be scared?
It’d be cool if mobs reacted when one of them dies nearby. Maybe they run off, hesitate, or even try to hide. Would make fights feel more dynamic and kinda realistic. Imagine creepers backing off when you smack one with a sword, or Pillagers regrouping after losing a few.
Not saying every mob needs to panic, but some kind of fear response would make combat way more interesting.
Anyone else think this would be fun?