Though I agree that genetic diversity is important and necessary, I also think of breeds in general. Each type of breed and their characteristics wouldn't be here if it wasn't for in and line breeding. A lot of traits we attribute to certain breeds are recessive, and wouldn't be there if it weren't for those techniques. I don't think ameteurs should attempt inbreeding, or linebreeding, especially if you don't have a full grasp of what you're doing, and are not willing to keep and cull hard the inbred progeny for health. With the populations we have access to in dog breeds today, outcrossing is a far safer way to go. Select for type and temperment and match accordingly. Never try to "correct" but compliment traits in two dogs.