Quote from stroheim_cornell
Yeah I was trying to wrap my head around how this would work for something like ww on Wiz or elemental arrow on DH. Kinda hurts the head to think of an elemental arrow shot that has all those attributes but could be pretty cool. Or try to imagine rapid fire with all its runes. That is the one I see likely not making it to release or if it does being very limited to specific skills or with some sort of diminished % on the overall damage or effect of said runes.
I guess you'll get the opportunity to use the same skill, with differents runes, several times in your skill bar. You'll get to have the same skill on your skill bar four times, but each with a different rune. You'll be able to use Fists of thunder quickening on left click and thunderclap on right click.