And sysctl is arguably more of an ABI than debugfs, which
doesn't really sound suitable for workaround.
And I don't see how adding a line to /etc/rc.local is harder than adding
a line to /etc/sysctl.conf
Adding a line is equally difficult both ways, you're right. But aren't
most distros better equipped to manage (persist, modify, automate) sysctl
parameters in a standardized manner?
Whereas rc.local seems more "individual need / edge case" oriented. For
instance: changes are done by editing the file, which is poorly scriptable
(unlike the sysctl command, which is a unified interface that reconciles
changes); the load order is also typically late in the boot stage, making
it not an ideal place for settings that affect system processes.