If you cripple a Raider's leg, just one mind you, they will attempt to run away. After getting about 30 yards from you, they seem to have a check in their AI. Some crippled Raiders will keep on running, and I usually just let them go -----> I fire a couple rounds in air over their heads just to make my point. I might say in real life,"Yeah! Keep running mofo!"
Some crippled raiders will turn around and come back at you, they probably figuring, well I'm about to die anyway, might as well make it good.
But yes, I agree. If I was a raider and came up on two people and a dog, and one person is wearing power armor and carrying a heavy incinerator (my current party), umm yeah, I'll be leaving now.