Your statement that -
"In many ways death was far less clean in WWI than WWII. It was due, in the main, to the iron casings of artillery which sent out huge mangling chunks of iron when exploded." - implied that those iron casings were no longer flying around in WWII, so death was cleaner then. I responded that those same chunks of shrapnel were flying in WWII and, indeed, are still flying to this very day.
Death may have been less clean in WWI because of the lack of antibiotics, or the general state of medical technology, or the fact that they lived in mud-filled trenches for four years, but shrapnel has been a battlefield constant since exploding shells were invented in the 15th or 16th century; so I guess I don't understand your juxtaposing those terms.
I'm not trying to be deliberately contentious, or just a smart-a$$; I'm just explaining what drew my initial response to your post.
Once again check the statistics. There are numerous autopsy reports regarding the nature of the wounds received in WWI compared with WWII. Common sense indicates that when troops were massed in trenches an artillery hit expelling large chunks of iron casing would mow down and dismember many men. There are numerous reports of human entrails hanging from trees, flattened men filling the bottom of large holes. The troops were more spread out in WWII. The mass of artillery fired in WWI was far greater than WWII. If I remember the dates correctly during the month of March 1916 during the battle of Verdun the Germans fired 5000 guns, 24 hours per day, for the entire 31 days. The wounds statistically speaking were far more horrific in WWI than WWII. That is based upon actual autopsies.