I'm really curious, is there any point for this kind of limitation thing? I'd love to see some skills tweaked to be made castable on both right or left mouse buttons. Nova especially should be allowed, Blizzard, Frost Nova, etc.. Maybe all types of 'battle' skills can be both buttons but curses/enhancements are limited to right button?

Dunno, just a little tedious to keep mashing hot keys for a couple of skills that won't go beyond right mouse buttons.