Dont know how I forgot about the P38, senior moments coming way too often now ! The decocker is special for me because I grew up w Colts and I'm sure you heard as many horror stories as I have about lowering the hammer. I was and continue to be amused at Sigs example of this when can be simply attached to the safety.
HK moved it to the slide on the P30 and I believe this to be a mistake but HK doesn't "do" anything w/o a reason, and I just don't know why they did it.
Was recently at range and the guy next to me was having clip "issues" w his reconditioned P38. As you already know, the P38 was designed to replace the Luger. What I find interesting is how manufacturers respond to problems. Feedback from the front was negative, tight actions do not respond well to dirt and lack of maintenance. What did the engineers do ? They designed a better holster to protect the pistol from the elements and passed out more cleaning kits. LOL.