Maybe as part of the existing prayer tree or as a side grade - that lets advocates bless neutral characters (and maybe gain exp if their blessed people gain MO?)
Why you ask?
Think of the poor NC in a good fac who wants to be 0 MO to do their balance thing. But that means they can't be blessed!
Then look across the river at the vassaled NC at 0 MO - can be summoned check! can be res'd check! can use a dark pact check! And can also still do their balance thing.