While we're dreaming about perfect breeding practices, I would love to see more attention paid to breeding dogs that will be companions for us "pet people," who are actually in the majority. Too often we get the puppies that don't make the cut as show dogs and I suspect that the structure of competitions tends to move the breed towards athletic, high-energy dogs who may not be ideal for family life in an average home. That may contribute to the number of Goldens who end up in rescues or shelters.
I think that a majority of hobby breeders are very concerned with temperament. Every show dog I personally know is first and foremost a pet in the home. Yes, show dogs do have a more successful career if they have a showy personality. This however does not mean flighty, fidgety, or unsuitable to be a house dog. It means a good on/off switch.
To see this stand ring side at a large show you will see lots of dogs stand patiently for quite a long time, in close proximity. Then when they go in they flip the switch and it is show time. Athletic, high energy, or showy attitude means nothing if a dog can not gait properly, stack and stand for thorough examination or free stack. This all seems easy until you try it.
I know not every breeder crosses over to do conformation and something else like obedience but my girl is a great example. She was shown at 7.5 months old to an AKC group 1 puppy and then we literally ran over to the evaluator and passed our CGC the same day. As I type this now she is 12 months and is chilling out while laying on my feet.
There are always different activity levels in a litter and some lines do run "hotter" than others. I know of breeders who specialize in high energy working goldens in obiedience, field, or agility. These breeders are very careful of who they place their dogs with, so the energy level of the dog is appropriately matched to an owner that wants and can handle these highly driven dogs.
I really do think I boils down to telling a breeder what you are looking for in a pet and find a breeder that you trust.