IIRC the casualty rate for bomber crews over Europe in 1942-44 was the highest for any allied combat unit anywhere, air OR ground. It was supposedly the most dangerous job in WW2. The German submariners may have had it worse, though. It'd be an interesting (if grim) investigation.
The insistence of the B-17 to do daylight bombing was part hubris, part over-estimation of the capabilities of the Norden Bombsight. The Norden was good, but the German counterpart was every bit as good. In retrospect, shifting more 8th AF operations to night area bombardment would have been wise, and saved a large number of crews and airplanes.
It is true that the B-17 ended up being a bit of a glory-hog, and Lancaster (and Liberator) crews were a bit bitter about it. I'm not sure of why this happened, as all of the heavy bombers did a superb job.