You can use it to load extra sectors for booting as needed (Some systems do this for some reason.), I highly recommend it not being a Kernel ,though.
It is very hackish, and does not use any file system of any type. It is much more better to treat the kernel as its own task/program for design purposes for cohesion. There is no possible way to do this by reading/writing random sectors off disk.
Also, some/most/mabey all filesystems use certain sectors for specific purposes. For example, FAT12's first FAT table is located directly after the number of reserved sectors after the bootsector, or directly after the bootsector. Reading/Writing random sectors may make a file system impossible to design and develop on that system.
A system without a filesystem has almost no nice way to treat "files" and "programs", as there is no standard structure for their storage on disk. Hence, say goodbye to Program Management - A core function in any OS.
I am sure many members here can come up with countless of reasons why this would be very bad for a kernel.
If you still wish to continue,
This might help you.