sys-kernel/genkernel frequently issues unnecessary warnings for kernel parameters "that *may be required* to boot properly", such as dozfs or domdadm, even if you are already using them. How difficult would it be to make genkernel *NOT* warn that you "might need" keywords that you're already using? Not a functional problem, just a recurring minor annoyance that could lead a user to ignore warnings they actually should have attended to. It's a "Cry Wolf" problem. Reproducible: Always
Ideally genkernel would need to learn to read the config files of every bootloader available... grub, lilo, refind, systemd-boot, built-in cmdline for efistub, and probably more. More realistically, someone could add a check for grub which would cover the majority of users. But even more realistically, genkernel is not being actively developed so this is probably not happening unless you can submit a functional patch for this. We could also just reword the warning a bit to be a bit less scary.