See this prior NH submission [1], and inthe G+ post he mentions fairly early on why it's important to be very quick in the boot process, and how DHCP figures into that. (TL;DR using VM containers that can normally boot within 100 ms, getting the DHCP server to respond within 50 ms means on-demand container spin-up for a specific request is possible)
I'd be interested to know if the systemd boot process (which can be 2 seconds or quicker) has enough advantages to make the other changes worth it.