Because Haley, they want them to look like the American bred German Shepards!
For low level eventing, he'll be fine. I had a saddlebred mare that had a better topline than him but waaay longer and had a very short upright shoulder. But she had a heart of gold.
Where you're going to run into trouble is at training level. They introduce lengthenings in dressage and your horse is not built for it. To compensate, just be correct and you'll get decent enough scores. Also, the jumps get quite wide and he'll probably have the 'up' scope, just not the 'across' scope needed to get across the big square oxers and spreads.
And when you think you're about ready to enter a dr show, be sure to practice the halt at x! I decided to practice that 3 weeks before my first test. And my horse, being a halter queen, halted square, then started parking out! Agh!
To help with the giraffe impression, relaxed SLOW gaits. Go very slowly. And do a lot of lunging with side reins set as low as possible with the nicest bit you have.
Good luck! Hope your saddlebred is as wonderful as mine was!

Average, for horses with some experience at this level