Per Wikipedia, the '73 did have those kind of improvements:
The chassis design was as new as the bodies - with an all-new, sturdier perimeter frame, new chassis/body mounts, larger 8½ inch rear axle, wider 6-inch wheel rim width, refined rear control arm bushings, increased front and rear suspension travel, new shock absorber location, and improved front suspension geometry - The left wheel was adjusted to have slightly more positive camber than the right which resulted in a more uniform and stable steering feel on high-crown road surfaces while maintaining excellent freeway cruise stability. Clearances for spring travel were also improved for a smoother ride over all types of surfaces; the coil springs at each wheel were computer-selected to match the individual car's weight. Front disc brakes were now standard on all '73 Chevelles. John Z. DeLorean, Chevrolet's dynamic general manager during the design phase of the new Chevelles, left just as they were being announced. He departed in late September 1972 to start a brief stint as vice president of General Motors's Car and Truck Group. DeLorean left the new Chevelle an important legacy, though. He and Alex Mair, then Chevrolet's chief engineer, championed great handling. Critics compared the GM Colonnade line favorably to Ford and Chrysler intermediates which had unattractive styling and less interior room.