I agree and have seen the same thing with dogs getting better or worse with new handlers. However you dont train a bird dog to point a pit to be game or a hound to track its just in them from years of line breeding. A cur dog bred properly will hunt and hold bay for hrs, line breeding increases your odds of every avg dogs from the litter doing this well. If the trainer will stay out of the way and put them on hogs you shouldnt have to be a great handler. They need to know come, load up, and hopefully get ahead is in the dna. i cant wait until my father to daughter pup gets here!
you are right there are some things you cant train, but a good handler can bring out the best in a dog.