With the 4 piece, the Ascendance cooldown works out to be 2:10-2:20. With different fight lengths, this can be a dps loss due to getting the same number of ascendance's out, but the 3 minute ascendance doing more damage from potentially lining up with skull banner everytime.
I'd say scrap the 4 piece and create a new one attributing to the lightning theme, or change it so its a 2 minute cooldown