Unless something has changed, firestorm has rolls on both its fire and divine portions. Worse still, if the first roll is evaded, the 2nd roll is auto-evaded.
Same goes for sunburst: reflex vs damage, then vs blind, so builds with evasion have 2 chances to avoid the blind.
If firestorm can still hit for 80+80 though, then
http://www.gondorvsmordor.com/gvm1/wiki/index.php/Firestormisn't working.