I strongly disagree with whoever said a GSD without a sloped back is a waste. A GSD with a sloped back is a showline dog. A GSD with little to zero slope is from the workingline class. This "someone" is talking utter nonsense.
Showline dogs were actually a mutation. An undesirable mutation. The Americans promoted the GSDs with exaggerated slopes. The original German Shepherd didn't have a sloped back.
Secondly, showline breeds tend to develop hip dysplasia frequently. I personally find workingline GSDs more appealing. Showline dogs look like they have broken backs. Im sorry if i offended most of you, but this is just my opinion.