Also, a male giant breed who matures way later than other dogs...
Physically, yes. But I think all males mature mentally at about the same rate...late.
It's obviously really complicated, so I wouldn't take a fearful adult as proof, per se, that the dog had below-average stability of temperament, but I think one of the defining characteristics of "good temperament" is that the dog is relatively durable in the face of bad experiences—
You know, you actually made me think differently of Chance's temperament because of this post. He shies away from anything/anyone new, but has a great disposition. When we first had him he was in a lot of pain because his previous owners didn't have him on any pain meds for his ED. He could hardly put any weight on his right leg.
On the first night with us he was sleeping in our living room and my daughter was dancing around in there. Well, she tripped and fell right on top of his bad leg.
He woke up startled and went limping into the other room. It must have been so painful for him, yet he didn't snap at her or anything like that. My daughter started crying and Chance heard her. He immediately came over to her and kissed her face.
So even though he would never pass the CGC, I do believe his temperament is wonderful.
It's getting converted into a title probably so the AKC can make money...I just don't think there should be an age requirement not allowing puppies to take it...
I don't think anyone said that puppies shouldn't be allowed to take it, only that it may not give a clear indication of the dog's adult temperament. And if it's to make money for the AKC, (which I agree it probably is), then maybe there should be different tests for different ages and the title is only given to the dog when the adult age appropriate test is passed.
I do agree, that with maturity comes the real temperament that you will see... But in a golden, especially, you are not going to get a dog that goes from having a terrific temperament to being a freak.
But you could very well have this happen in a Working Breed. Maybe not a "freak", but definitely there could be some changes.