I realize this is beating a dead horse, but it really is a shame that microkernels didn't win for human-facing Unix systems. This issue was recognized and basically solved decades ago, and we're still almost there.
I do wonder what this landscape could have looked like if all of the effort had gone behind a Mach-based microkernel. I read all of the back and forth between Tanenbaum and Torvalds. At the time, I was just so excited to see "free and open" winning.
I should specify that the XNU Kernel from Darwin/OSX took a lot of my attention when it first premiered.
Had the servers been running microkernels instead, updating services without full restarts would have been trivial in almost all cases.
It's just a better approach overall. I curse the path dependency that led to the current situation.