How can omitting an exposition repeat change the balance of a sonata-form movement?

Omitting the exposition repeat in a sonata-form movement significantly disrupts the intended proportions and dramatic structure of the work. Because music relies on the controlled use of time, altering the temporal structure by skipping this repetition changes the balance of the entire movement.1

Specifically, the exposition repeat is designed to establish a sense of regularity. When this is ignored, the thematic balance of the movement is upset, and the dramatic impact of the development section—which is intended to function as a sudden departure from that established regularity—can be ruined. By failing to follow the composer's instruction to repeat the exposition, performers risk undermining the structural integrity and the carefully crafted proportions of the musical argument.1