In the past I've replaced some plane blades with Hock or Pinnacle irons in the belief that the thicker steel would reduce chatter and make the planes work better.  So I was going to get a Hock blade for my Stanley No. 53 Shave, but a call to Ron Hock was very instructive.  He said:

1. A thicker plane iron is not in itself an advantage.  His irons are better because he uses better steel than most newer planes and it is hardened to hold an edge better, not because they are thicker.  Ron says the pre-war Stanley irons were great and he does not recommend swapping them out.

2. It's his heavier chip breaker that imparts greater rigidity and improves the performance of any blade.  I can attest that buying a Hock chip breaker for my No. 113 compass plane greatly reduced chatter and improved its performance.

So in summary, the performance of a pre-WWII plane can be improved with a stiffer chip breaker.  When replacing newer blades make sure to upgrade the chip breaker.