The Cowboys, on the surface, are built to win. They have solidified their defense- whatever needs they have left can easily be picked up in the draft and free agency.
They have the best offensive stars in the game as a whole, and in light duty the Cowboys engine purrs like a kitten with the roar of a high powered engine when they rev up the engine.
But the coil in their engine is bad. The main part that provides the spark that keeps the engine firing on all cylinders is weak. Under heavy loads that coil cannot keep up. The rest of the engine struggles because it does not receive the spark from the coil when the engine is under duress.
Because of that weak part, the nicest car with the most powerful engine is as useless as a junkyard beater.
This is how Jerry must look at the Cowboys. He can put anything on the car to make it better looking that he wants to, but unless he fixes the coil, it will continue to sputter every time it comes to a hill.
He needs to fix that one problem before he dresses up the rest of the team, or he will continue to have the nicest car on the lot that he can't depend on to go anywhere.