PM, your dogs have one trick but it's a GREAT one. It's a guardian breed, one of the oldest and best examples of this type of dog. It's no insult to say it's a one trick pony, it was bred for a purpose and that's what it does, and does it very well. However, comparing them to a GSD is really irrelevant, because both breeds were created to do different things. So don't take it personally. The GSD is a versatile breed that can track, protect, herd, guard, assist the disabled, or perform in sports like obedience and agility. Their versatility is what makes them special. That versatility is also what was part of their demise, in how the breed has gone downhill. You don't need to prove anything- most GSD owners know the dog isn't what it used to be. Just like so many other breeds that have been exploited by breeders and breed clubs who change the breed standards to suit their less than adequate dogs. GSD owners also know that there are enough breeders who strive to preserve the breed for it's original traits.
You are lucky that your dog has not been "discovered" by the show ring breeders and had it's great traits bred down to create a fluffy teddy bear that looks nice in the show ring and can't do anything else except sell puppies to the public. I think it takes a special owner to be able to deal with some of the LDG breeds and you have shown that in the success you've had with your dogs in areas outside their breed's general use, such as the TDI and show work you do. Just as it takes a special owner to deal with a good GSD. Both breeds have their needs and owners who know how to deal with those needs. That said, for someone looking for a dog that can be a family companion, deal with strangers and visitors in the household, be good with children, but be protective when needed, the GSD is the dog for that job. My guess it's easier to train a working line GSD to protect than it is to train a really good LDG to accept strangers in it's territory. I'd trust my dog in that regard over an LDG who thinks on his own and has more of a one track mind. I'm the one who decides when it's time to protect, not my dog, and when the dog makes that choice, that's where you have problems. What if you are doing a TDI visit with your dog and some old person slips and falls into you and the dog thinks it's time to protect?