I honestly don't mind mixed breeds to an extent. But breed a dog for a purpose, I've seen enough golden retrievers that don't retrieve, hounds that don't smell, terriers who don't hunt. If you want to mix your two best cattle dogs because they have great cow sense, all for you. Those dogs have a purpose. I would love to see today's german shepherds with sheep, or beagles after rabbits. But it's fine for those dogs to be pets too, just have to breed traits please.
All for health checks, my own border collie is clear for hip, and eyes, and so it's his parents, grandparents.