I think it's the responsibility of a breeder to adopt ONE standard and stick with it. One breed specific standard. Except, I think show breeders should pay some attention to performance - just because I feel that the majority of dogs should have some purpose in life, and it helps give a breeder an objective evaluation of trainability and temperament.
Dogs that are still 100% working bred like working Border collies, are really a special case in this discussion. My Border collies are kind of in flux right now, so I'll talk about my Marremmas. These dogs are almost strictly bred for work, very hard work. That work dictates their structure, health, and temperament, besides of course natural working ability. In spite of their being a giant breed, they typically live and work well into their teens, suffering from very few ills. Joint problems are pretty much non-existant. Their coats shine bright white and don't smell, even though they live outside with livestock and don't even shelter when it snows or rains (except very hard). Heck, I don't even use flea and tick stuff on them - and they test free of stomach worms every year though I've never used wormer on them (they get ivomec for HW). Somehow they are naturally resistant to parasites.
I know of few sights more stirring than a Marremma sprinting across a field to meet danger - and at night you cannot hear them approach in the darkness no matter how fast they are moving. As to temperament, you should see my 150 pound Tully playing with a kitten, or puppy, or my preschool son. His sire would lay down, turn into Pancake Dog, and gently touch my youngest when he was two, trying to get him to play. You can't have a rough, mean dog in charge of 4 pound lambs. Tully lays down next to a lamb that is just born and keeps it dry while its mother is giving birth to the twin. It makes me a little choked up whenever I see that.
All that makes a very nice companion animal, too, for the person who is prepared to handle the nature of the dog - and if you are not, why would you want such a dog for a pet? They are gentle, clean, humble, fiercely loyal, smart as heck, shed very little most of the year (you can make a sweater or three in the spring), and healthy and longlived.
No show ring judge can keep together a package like that. It's a fact that if you start narrowing down the gene pool to select FOR showy qualities (head type, angulation, gaits that the dog doesn't use working), the working qualities will suffer. The work is what holds together the balance in a dog like this - breeding for anything else will rapidly break down the breed's health, temperament, abilities.
Why is this? If the same dogs are being bred, why does the breed change in its essential characteristics so quickly and dramatically when the breeding focus changes? Because working breeding maintains balances - high drive balanced with biddability, extreme athleticism balanced with soundness, reactivity balanced with impulse control, instinct balanced with sensitivity. Notice how many of these working balances focus on temperamental issues. And the only way you can evaluate any of these characteristics is through advanced training.
This balance decays within a couple generations from the advanced working generations. Now I'll switch back to the BCs since I've seen this - am seeing this, actually. Working BC people are well aware of the two generation limitation. You have to breed TO the working standard at least that often, and more often if you want to maintain the working ability down the road (ie, founding a line versus a terminal cross). This is the main reason for the trials - to maintain a pool of superior dogs to cross back to and improve farm lines.
I believe possibly with hunting hounds the instinct is maintained much longer, as an aside - I'm only speaking within the working world I'm familiar with.
Now border collies are being bred for a variety of other reasons. Athletic ability without the extreme hard work that screens for a well-rounded soundness. BC joints are very lax but working dogs have extremely strong connective tissue - this arrangement allows for extreme flexibility:
http://www.pbase.com/cdwall/image/50647162
If you maintain the laxness but do not ensure that the connective tissue strength is maintained, you will start having problems with hip and elbow degeneration. If you "square up" the joints AND do not ensure connective tissue strength, you will end up with connective tissue injuries.
People who are taking dogs from working lines (for their high drive) and breeding them for sport, are constantly being disappointed that the soundness does not hold up in successive generations. They blame the working breeders for not "health testing". But the conformation lines are disappointing in their drive levels. Attempts to mix the two can produce the worst of both worlds. Really, the sport people are attempting the impossible - taking two gene pools that are not suited for what they want (the gene pools, not the individual dogs) and attempting to create out of them a gene pool from which they CAN get dogs that will do what they want.
Does that make sense?
This is why I'm adamant that breeders stay true to ONE standard, when you are dealing with a working breed. Sport breeders are becoming infamous for going through dogs like stale candy bars. I hate to see that, and I hate that they are watering down the breed with what they are doing. For instance, there is a deadly heritable disease that was restricted to the conformation lines for many generations. Thanks to the sport breeders in the US, that recessive gene has now been introduced into the working studbook.
Well, I could talk all day about this (I practically have, it appears).