Additionally, DnD has many more instances of other complicating factors that mean that adding further detail to the combat just further overloads the system. Would I want DnD to have hit locations? Probably not. I am already tracking 3 different types of buff from various different sources, bonuses that only apply in various specific situations, and varying time limits on various things. 40k? Usually everything is on my character sheet. Occasionally I have to keep track of the length of some sort of status effect ("Stunned for 3 rounds"), but overall the combat complexity is lower, at least in my experience. The additional "burden" of hit locations doesn't feel overloading.

DnD's complexity is why I've switched systems in the first place.

Just because DH is more elegant in some ways doesn't mean I can't prefer more simplicity when accessible.

Variable armor on character bodyparts is a rule I do not use, due to the extra steps it requires. It's nothing more complex than that.

Any measurement of how much more complex isn't useful, since what is for me more extreme, is routine for you.

Overall though, I find it easier to simplify a given complex rule than to add in complexity for a simple one that doesn't do enough. So if anything, all I'd ask for is a 'house rule' section at the back with a steamlined alternative for those who would like it, without punishing those who desire more crunch.