The standard temperament for a GSD is...Temperament is confident, fearless but aloof; eager, alert, and willing to work. If the dog comes from a good background it will have all the traits you are looking for. If you just want the dog as a deterrent, then you are off to a good start. Others will chime in, but my belief is that you don't want a dog that will bark at everything or attack everything..you want a dog that can tell the difference between good and bad. My GSD loves people, but she doesn't go out of her way to approach strangers, if its family then she turns into a excited puppy. She was heavily socialized with other dogs, cats, people, little people, etc. When she was younger I allowed anyone that asked to pet her, but again I must say that if we go to the pet store now she doesn't approach them, but they(mostly the workers because they have known her since she was a puppy) will approach her and she will accept it. She doesn't bark at everything, so when she does bark I know something isn't right.
Misty- Samoyed Mix, Tannor- Golden Retriever CGC
Robyn- GSD CGC, TC, Midnite-GSD CGC,TC, Brennan-Golden Retriever CGC, Batman-Husky/Greyhound , Apollo-GSD