Could you please elaborate on what you mean by "baggage"? I apologize if it's obvious and I just missed it! :]
"Why shouldn't an Assistance Dog be protective?
" See the link I posted.
Not my call or experience, I just look for patterns in that pattern, Labs and Retrievers make up 85% of the seeing eye dogs GDS's are 15%.
Another dog (one of my favorites) that could make an excellent service dog would be a Boxer...if you have a lot of time on your hand! It would take 3 times as long to train a Boxer as a service dog as it would a GSD! Most pro's don't have that kind of time to devote to a single dog.
Oh and forget the King Shepherd anyway...to big.
And from my experience I had about 12 years training and handling dogs all Bully breeds my GSD handed me my butt! I had to really up my game to deal with his "protection/people issues."
I did and he's fine, my "guess" would be that 'Seeing eyes for the Blind' doesn't need that kind of crap with the dogs they place?
But to your point with a GSD, you need the right dog, with the right temperament, from a good breeder! And you need to have your game face on, anything less with a GSD and it might not work out so well.
Another link general info:
New Dog, Very Challenging
"Who pets my puppy or Dog" is how I train all my dogs.