I agree! I’ve had the weak nerved dog and it’s not fun. I never want to go back to that again, EVER.A sharp defensive dog with lots of aggression and a low threshold, or a sharp defensive dog with lots of aggression because of bad nerves. I myself like the first example. A fear biter not so much.
As far as litters differing or not every pup having stellar nerves. A good breeder should produce predominantly dogs of good nerves. Meaning confident, social, pups. not every pup will possess the same drives or extremes when it comes to those drives. But, I would hope that a breeder who has a bitch or stud that consistently produces nerve bags would stop breeding that dog.
Per if the dog bounces back, I would say that it would take a combination of good training and the dog having good enough nerves to bounce back..Best to not put the dog in that situation to begin with. But the **** happens.