Well my experience in other MMO's as a healer i found it usefull that the default self cast modifier was "Alt," so I have gotten used to it.
I have played a jugg since launch and did not use the self cast option untill i just recently switched toheals on my level 40 sorcerer. Therefore, I would like to use what I am used to already if that makes sence. I have too many other keybinds within reach of my left hand to apply it to something eles. "Alt" is unused atm, and other keys such as "Shift", "Ctrl", and "Tab" all cannot be used as self cast modifiers... also the default "Home" key is a compleatly unviable option, seeing as I would have to take my hand compleatly off of my mouse or move my left hand over and stop moving for that durration.