Community wiki was some sort of crazy consolation for list-posts invented in the early days of Stack Overflow. I don't think they really have much of any place on this site and I never would suggest anyone use it here.
Community wiki should not be used as a cop-out for not wanting to accrue downvotes. If someone answers a dumb questions that they don't want their name on (like Was Jesus a Time-Traveler) then they should bear the responsibility for answering that question.
Possibly, the https://christianity.stackexchange.com/questions/tagged/chrestomathy-request posts should be CW and some denomination surveys. The tools are to build up the site and the facts, not to avoid personal responsibility.
I do think CW can use used to mitigate the risk of answering, but not completely negate it. If the risk/reward ratio for answering a normal question is 1 and the risk/reward ratio for answering a terrible question is 0.2, marking it CW may bring the risk/reward ratio back up to 1. But if the risk/reward ratio for answering a kind of bad question is 0.8, then marking it CW may bring it up to 1.4 - so that's what I think we should avoid.