For the record, EM makes your next CL, LvB or LB instant, it's (no longer) not related to crit, but gives a 15% spell haste buff for 15 seconds. It basically makes FS & LvB go off at the same time. The only waste i see here is that it's not using the longest cast (LB). The burst this way is pretty nuts, which is prefer for the way i play.