Ubuntu - not a big deal

They still use upstart in sysvinit-compatible manner, i.e., to get to the runlevel 2, run /etc/init.d/rc with parameter '2', which in turn runs each of /etc/rc2.d/S??* with parameter 'start', and so on. You still could revert between upstart and sysvinit, and between /etc/inittab and /etc/event.d as you wish. Nothing of these fancy dependency tracking and startup order optimizations is ever seen.