As SirDice was kind enough to point out,

you shouldn't allow any kind of program that has more than one function, let alone a function to edit / open files as the root user to be used with sudo (in the /etc/sudoers)
That way noone will be able to edit the /etc/shadow, /etc/password or /etc/sudoers or even worse files . . .

The only file allowed to be "su-done" on my system is a shellscript that chroots the home of the user and then drops back to the lower rights user..

The only thing you have to be realy realy carefull about is not to allow to much !!!