I just read a biography of Lucian Truscott Jr., who was along as an observer at Dieppe. It was indeed a disaster, and squandered many well trained men.
The most important thing in war is to learn as much as possible from the mistakes you make. The learning from mistakes at Dieppe was used to help assure successful landings in North Africa, where Truscott was Patton’s deputy.
Some of the Canadians who came back became the nucleus of the First Special Service Force assembled by LTC Fredricks (Later MG), which benefited greatly from the Candian’s experience. They took part in the amphibious retaking of Dutch Harbor, and had later operations in Italy. Many of the US soldiers left went to the 45th Division. Major General Fredricks went on to found US Special Forces as Commander of the Military Assistance Group to Greece.
One interesting thing I discovered was trying to find accurate descriptions and books about the battle/massacre at Dieppe(although while I was there in ‘94 the local citizens were extremely rude).There are or were very few books out in 1994 about Dieppe although that may have changed by now. The cemetary itself is extremely impressive and the forces faced an impossible task, while the response to action to collect the troops from the British side was nothing short of miraculous!