I completely agree with your three points.
Now it seems to me the problem with meta comments is that they are more expensive than normal comments.
As an example, if I write "tomorrow a robot army from China will destroy the world", people can agree or disagree, upvote or downvote, but almost nobody thinks it is the topic which needs to be discussed, and there is almost zero risk that it will spawn half dozen meta articles tomorrow.
On the other hand, if I write "Eliezer is censoring this website and I am so going to write an article on RationalWiki about that", suddenly most people want to express their agreement or disagreement, then I can go more meta and say "everyone who downvoted me only proves that LW hive mind is insane", then a few confused contrarians will upvote my previous comments, to keep the controversy alive, then Eliezer joins, then a new moderation rule is proposed, half dozen meta articles are written, etc. Am I right?
Then it seems to me the best solution is to make writing meta comments more expensive, too. To make sure that people don't start a nuclear war over triviality. If it is not worth for anyone to spend a few minutes preparing a solid argument, then it probably is not so important.
I propose this rule: Meta discussions should be forbidden and censored in comments on threads with a different topic. (How would you feel if you spent an afternoon writing a nice article for LessWrong, only to see that the discussion goes off topic and finishes in a flamewar about something completely unrelated to your article.) However, meta discussions and other forms of criticism are OK in form of well-written articles. Within some reasonable limits, of course, to prevent dozen meta articles on the same topic, or by the same person.
If it is not worth making a well-written article about, then it probably is not so important.
Also I would recommend a policy that meta comments and articles should be downvoted unless you agree with the argument and the way it was presented. (In other words, don't be "useful idiots" and upvote trolls only to protect the diversity and fight censorship.) No, it does not mean that all constructive ideas would be supressed. Let me remind you that ideas like "make a separate subreddit for meetups" are typically upvoted heavily. Even the discussions about what is taboo and what is not, or the current minisequence connotationally accusing LessWrong of sexism, are relatively well accepted. The criticism of SIAI by Holder was upvoted and thoroughly discussed. So if something is not accepted well, let that be an evidence that there is something seriously wrong about that, and that it deserves to be downvoted and/or removed.
Every time you feed a troll, remember about the costs you have caused to everyone who has to deal with that. (I should more often remind myself about that, too.)
Meta discussions should be forbidden and censored in comments on threads with a different topic. (How would you feel if you spent an afternoon writing a nice article for LessWrong, only to see that the discussion goes off topic and finishes in a flamewar about something completely unrelated to your article.)
The problem with this rule is that on the same topic is not well defined. Arguably, the appearance of rituals to outsiders was on topic in a thread about rituals performed by some folks in this community.
After a recent comment thread degenerated into an argument about trolling, moderation, and meta discussions, I came to the following conclusions:
Ideally, Less Wrong would implement a separate "META" area (so that people can read the regular area for all the object-level discussions, and then sally into the meta area only when they're ready). After talking to Luke (who also wants this), though, it seems clear that nobody is able to implement it very soon. So as a stopgap measure, I'm personally going to start doing the following, and I hope you join me:
Whenever a conversation starts getting bitterly meta in a thread that's not originally about a LW site meta issue, I'm going to tell people to start a thread on the LW Uncensored Reddit Thread instead. Then I'm going to downvote anyone who continues the meta war on the original thread.
I know it's annoying to send people somewhere that has a different login system, but it's as far as I can tell the best fix we currently have. Since some meta conversations are important, I'm not going to punish people for linking to meta thread discussions that they think are significant, and the relevant place for those links is usually the Open Thread. I don't want LessWrong to be a community devoted to arguing about the mechanics of LessWrong, so that's my suggestion.
Thoughts? (And yes, this thread is obviously open to meta discussion. I'm hopefully doing something constructive about the problem, instead of just complaining about it, though.)
EDIT: Changed the link to the uncensored thread more specifically, at Luke's request; originally I linked to the general LW subreddit, which is more heavily moderated.