When considering the dog as a whole, also consider WHY he was bred. A Boxer must look to be able to fulfill his original purpose, even though not required to do so in this modern world
There are many schools of thought as to why and how the Boxer as a breed came into existence, but we do know the Boxer was a man made breed in the late 1800's.
His ancestors, the "Brabant Bullenbeisser", a Mastiff type dog, were originally bred in Germany.

The Boxer 1896
As the breeders of that time wanted dogs suitable for hunting and holding prey, these dogs were then outcrossed with a smaller Mastiff type dog, (the originator of the the English Bulldog). These dogs possessed a wide undershot lower jaw, a nose that was set further back, and was a smaller and more active dog than the Bullenbeisser.
- This dog's strong and wide undershot jaw and strong teeth were needed in order to have him lock onto his prey and to continue holding it until his master arrived.
- His nose with its large, open nostrils, was set back in order that he could breath while holding on to his quarry.
- The wrinkles on each side of his muzzle were also there for a purpose which was to keep the blood of the animal away from his eyes.
This criteria for the perfect Boxer head still stands to this day.
The Boxer was later used as a guard dog, and can acquit himself quite readily to the job if trained to do so, but he is more temperamentally suited for Obedience work and Agility and a protector of the family home. He should be able to cover great distances at good speed and be a splendid jumper.
Any faults that would hamper this ability should be penalised far greater than any other.