Golf you a quine for great good! is a great example, since it was posted before the quine consensus was made. That means it's cluttered with answers not following it. Should we repost challenges containing a lot of answers affected by a consensus change?
No, We should update the old one
Challenges like the Quine challenge have tons of answers, and most of them are valid. Making a second question would either require all the existing valid answers to be ported over or would likely be largely incomplete.
Neither of these seem like feasible options to me. Porting them over would be difficult because a lot of these are answers were made by users of varying degrees of active, ensuring that we allow every user to keep claim to his or her answer while porting them in a timely fashion seems impossible. Being incomplete is also rather bad because it means that our Quines will be partially split between two questions which can be confusing and annoying. This is the kind of change that I feel we would really regret in only a short while.
I think the more reasonable option is to edit the question to reflect our updated community consensuses and delete the offending answers. This option is not without flaws but I think it is better than both doing nothing and reposting.
I'd say if they contain 20 or more answers not following current non-retroactive consensus that didn't exist back then, we should repost. I'd say that we should wait for 6 months until we repost or re-repost. Note that this does not include retroactive consensus, where old answers are supposed to follow, since then we can just delete them with a notice until they're edited.