Re: sysvinit & systemd
Serious discussion. Sysvinit doesn't work on modern systems where hardware is not static and buses are not hard-set (slot 1 gets assigned x and y, etc.). But if we want to adhere better to the UNIX philosophy, can't the differerent buses be delegated to dedicated subsystem programs, with whatever's at PID1 being just the coordinator, only needing to internally handle the baseline buses presented at bootup? It would still need to be able to handle events and so on, yes, but at least this way it compartmentalizes the control structure logically, say one program handles the PCI Express bus, which may have the USB controller attached so would in turn start up a USB handler, and so on.
PS. It's been a bit since I've dug into the innards, so if this is how it's done now, just mention it. But last I checked, a lot of the hardware support, including hotplugging, is still done in the kernel.