Wail of the sacrificed is an ability for the Advent Rebel's temple of communion unlocked at tier 7. When activated at a temple of communion, it kills the planet's population, leaving an uncolonized planet. For this trade off however, it deals out immediate damage to connected gravity wells, specifically 20 times the planets population. For example, if activated on a moon planet, it will deal 20*50=1000 damage to all connected gravity wells.
While it doesn't do much damage with asteroids/moon/volcano planets, ice/desert and terran planets, it's a different story.
Ice Planet Max Population: 160
Damage done: 160*20=3200 damage
Desert Planet Max Population: 190
Damage done: 190*20=3800 damage
Terran Planet Max Population: 280
Damage done: 280*30=5600 damage.
Realize that this damage is done INSTANTLY, meaning that there is no way to avoid it if you are at a nearby planet. Because of this, it is possible to lose entire fleets in a matter of seconds. One second I had 700 supply worth of fleet, the next second it was decimated from wail of the sacrificed on a desert planet. While you may lose the planet, and the population has to regrow, is well worth if it means destroying the enemy's fleet.
This only gets worse when an enemy has multiple planets clustered together, making it nearly impossible to attack advent rebels late game, not without risking the loss of your entire fleet. The only things that can survive wail of the sacrificed from ice/desert/terran planets are titans and capital ships, which are easy prey once their supporting fleet is killed.
My question to you guys is: is wail of the sacrificed to good in the late game? If so, what should be done to balance it out?