Not sure, I haven't actually tried it yet. It was just an idea I had.
In theory yes. Let's take a unit that is incredibly resistant to
Ld as an example, Deathshroud Terminators. Say they are charged by the Chaplain, a unit of 5 Vanguard, and a unit of 5 Reivers. (Not guaranteed by any means out of Deep Strike, but 7 up on two dice with a re-roll isn't super hard to make 3 times.) Say only 1 terminator goes down. Base
Ld is 9, -3 for each unit (Fearsome Aspect), -2 for Reivers, -1 for Casualty. Now their
Ld is 3 and because of the Master of Sanctity they have to roll above this twice. (Or if it was the Captain, their
Ld would be 2 but rolling a single.)
This is basically worst case scenario for the army, most units will get reduced to 1Ld pretty easy, even if only the Reivers connect.
That being said, there is a certain weakness in the Stratagem to Auto Pass Morale for 2CP. But that can only be used once per phase and if you are causing multiple checks you still kill stuff. Also, how much
CP can you dump into Auto Passing morale in a 1000 point game?