Community wikis haven't vanished, the rules have just changed. Now only moderators can convert an entire question (including all of the answers) into community wiki. But you can still elect to post an answer as "community wiki" to any question whenever you feel it is appropriate.
The reason that the rules changed is similar to what you suspected: questions that simply didn't follow our guidelines were being marked as "community wiki" as an attempt to skirt those guidelines and fly those questions in "under the radar", so to speak. Here, we're talking about polls, discussion-style questions, and other fun you might want to have.
The FAQ entry on the main Meta site explains community wikis quite well. Specifically, the rules on how a post becomes community wiki are:
- The body of the post has been edited by at least five (5) different users.
- The post has been edited ten (10) times by the original owner.
- The answer's author checks the "community wiki" checkbox when composing the answer. Note that this checkbox isn't available to new users.
- The answer is edited by its original author, who when doing so opts to check the community wiki.
- An answer posted to a Community Wiki question will also be Community Wiki.
- The question generates more than 30 answers (15 on Super User). In this case, the question and all answers will enter community mode, as will any future answers.
- A moderator has reason to believe that the question serves better in community wiki mode - if you want your question to be converted to a Community Wiki, flag it for moderator attention.
So the conclusion here is that if you see a question that you think needs to be made community wiki, you should flag it for moderator attention. Don't assume that just because the question was asked a couple of days ago, all of the moderators have surely seen it and decided that it should not be community wiki. We're just volunteers, not superhumans. That's what your flags are for; the community wiki mob was shut down a long time ago. (Of course, that doesn't necessarily mean that the moderator who processes your flag will agree with you! :-) But if you feel strongly about things like this, you should bring it to our attention.)
The way I see it, community wiki is most useful on answers, rather than questions. The point of community wiki is to lower the reputation threshold required to edit the answer and add updates or modifications of your own. The fact that ownership is transferred to the community and individual users do not accrue any reputation from the posts is merely a side effect or implementation detail. And now that anyone, including anonymous users, can suggest edits to any post, there seems to be less reason to make posts community wiki in the first place.
And yes, it is most useful on answers that are primarily a list. There are certain cases where lists make sense (for example, you'll notice that the FAQ entries are all required to be community wiki-fied), but in those cases, we should focus our efforts on a single answer, rather than everyone contributing an answer of their own. That's what community wiki is really for.
I've gone ahead and converted that question to community wiki for the time being. Long term, I think it should probably be merged with this one. And I don't personally see anything wrong with netting reputation from useful answers, even if they're to simple topics like "how can I get started in philosophy?".
Update: An article concerning community wikis has just been posted on the Stack Exchange blog. In it, Grace Note more clearly articulates the same issues and concerns that I tried to lay out above, namely that community wiki is less important now that suggested edits exist, that community wiki posts should not be used for "fun" questions or those that are otherwise off-topic, and that community wiki is best used for answers rather than questions. Read the whole article here: The Future of Community Wiki.