Let's first look at what Community Wiki posts do:

- Greatly lower the reputation requirement for editing the post
- Prevent the post from yielding reputation from votes
- Reduce the profile of the attribution

### Edit reputation requirement
A big issue with the reputation requirement on meta (the exception being MSO), where these [meta-tag:faq] posts are hosted, is that *there are no suggested edits*. An edit can only be done by higher-reputation users.  
[meta-tag:faq] posts are generally about *one* subject at a time, with *one* all-encompassing answer to that subject. This means that, whenever something changes about the state of affairs regarding that [meta-tag:faq] post, it should be easy to amend and update, rather than requiring someone with high-reputation to edit it. There is, essentially, no way (except for a flag) to inform these high-reputation users of the necessary edit.

That said, by the nature of the SE system, such a post would become a Community Wiki organically - after a given amount of edits it is automatically converted.

### Post reputation yield
That's a tricky one. See, non-MSO metas don't actually *have* reputation, so this seems irrelevant, doesn't it? Well, kinda. The reputation (or, rather, the computed votes) still exist, contribute to tag score and various badges.
The fundamental problem of *actual* reputation yield, however, is relevant only to MSO, so this can - largely - be ignored for non-MSO metas.

### Attribution
There's a big difference between how a Community Wiki post is attributed and how a regular post is attributed. A Community Wiki post is *much* more subtle, and points out rather clearly that the post is a *community* effort, rather than the work of a single user. [meta-tag:faq] posts are not supposed to be the work of one user, but a *community* aid, decision or other important notice. Attributing these (with the coverage they get) to a single user seems rather dishonest to the community at large.

### Conclusion
In my opinion, *especially* that third point is a good reason to keep the Community Wiki status on [meta-tag:faq] posts, even on non-MSO metas. More often than not these [meta-tag:faq] posts aren't even original content, but instead stripped straight from MSO, so it makes sense to go with low-profile attribution.  
At the end of the day, it's up to the individual site to decide, but I feel there are very good reasons to maintain this.