I have been trying a build where I cast Inferno, with the +10% crit rune on it, and with ~10% crit on my character (5% from items, 5% from buff at max heat). I've coupled this with the skill in movement that gives a 10% cooldown reduction on crit. It seems that Inferno is either not critting, or crits from Inferno do not reduce the cooldown on abilities (specifically Inferno).