Wrack and Ruin Value
A lot of people still don’t believe Wrack and Ruin are worth the slot, but I think it’s BiS (Best in Slot).
Just in case you are on the outside looking in, W&R hits everything in a 4 meter radius of a BB’d elite or special with soulfire (like the Psyker ult that melts the screen) but instead of waiting 30 seconds for an ult charge you can just do it again and again and again.
The secret is: the harder your mission the more value you get out of it. More stacked elites means more chances to stack SF.
I hope this info is useful, think about it next time you are BB’ing a Crusher surrounded by hordes, or even other elites.