John,
The short answer is that comparing to the Nobler, moderns ships tend to be bigger. The major changes are longer tail moments (flap hinge line to elevator hinge line) have increased by 10 - 12%. The area of the elevator/stab have increase from 18% up to 22 - 24% of the wing area. These changes allow the CG on a modern ship to move back to around the 23 - 26% of the average wing cord. Last thing is the power level is 25% more for about the same weight (larger diameter props can be used and the bigger tail area lets it turn). Most classic ships could hold there own with just a change to current power plants but would also benefit from the other changes also.
Best, DennisT