I am not sure he missed anything. There is no disk management functions through the web gui. If you install more disks you have to use the shell in order to manage your disks or webmin or some other program.
Even creating file directories requires either shell or another third party program. It would be nice to be able to manage the disks, mount points, software raid setup, and internal server directory structure straight from the web gui. This way people who are not very familiar with linux can start using it faster and not require either third party programs or command SSH prompt.