Please don't take this as a criticism of the staff, but...

Maybe the best thing would be for immortals with religions to be more straightforward about when they're going to be inactive, whether due to vacation, real-life commitments, loss of interest, etc. I get the feeling that, currently, if a staff member were to say, "I don't feel like empowering anyone for a while, or even interacting with morts in general," that they might quickly cease to be a staff member.

I'd be okay with imms jumping from "active" to "inactive" on a weekly basis if necessary, assuming it accurately represented those imms' true availability. Though, I can see how this might cause problems from a role-play point of view. Maybe make the inactive/active thing completely OOC, i.e. the imm's player giving notice rather than the imm character being destroyed, sent thorugh a dimensional rift, etc.