I'm OC about the smooth dome also. It just irritates me to no end to "miss" a spot on my head, even though I know I'm the only one who can tell. I sometimes try too hard, and that's usually when I end up with a nick.
The shadow never has bothered me, but I can tell its there, and wintertime is worse. I've used some sunless tan on my head before, but it didn't do much for me, plus I didn't like the way it smelled. I agree that the majority of people don't notice.
If its irritation, try different things and see if it improves; new blade, different lubricant, add more water, etc.
Keep the faith Professor!