If I read this right, systemd is about more than tweaking the way Linux boots. A few of the goals I saw mentioned:
1. Start fewer processes and only start them when they're actually needed.
For example, don't start cups unless there is a printer somewhere.
This could improve out-of-the-box security, which is always a concern.
2. Minimize boot time. This is very important for server admins trying to get to "five nines" of uptime. Sometimes you are upgrading your kernel or hardware, and you just have to reboot. It needs to be quick.
3. Manage the processes on the system. For example, put the updatedb process in its own appropriately configured cgroup. This should limit how much I/O and CPU updatedb can grab from foreground tasks.
4. Handle dynamically changing hardware configurations properly. For example, start the correct daemons when a bluetooth device is plugged in.
A lot of the "quirky interfaces" people complain about are things like automounting USB thumb drives not working correctly, or bluetooth setup. These are things that systemd is explicitly designed to address.