Great post, two additional comments I'd make -- stopping "bad" titles before they get posted, and other uses for the titles.
in reply to Composing effective node titles
The people most likely to submit posts with bad titles are also, in general, likely not to read the FAQs or other discussions on how to post well, in particular they are probably very new to PM, possibly new to online discussion in general; and although there may be guidelines on good posting available, the underlying problem isn't cussedness on the part of the poster, or even a belief that the title they're using is "good", rather I expect it is that it hasn't occured to them that the title of their post is an issue.
Is there virtue therefore in asking them the question -- is this a good title? -- for example, text adjacent to the title box when they post their Q? Whilst this won't help with the general never-reads-the-FAQs problem, it would mean that they are aware that there is a potential issue there, and may make them think about how they want to title their post, while at the same time being unobtrusive and ignorable.
Also, in titling (and re-titling) nodes we need to remember their use in searching, and that in particular searching is more reliant on keywords, and less on context, than a human is when scanning titles. To this end, as far as possible, titles not only need to be meaningfull to humans, but are also easyily findable by a keyword search -- not that you should be appending a selection of keywords to the title of course! Rather that we need to remember that, for example, a human reading a title can map "apache" onto "webserver" far more efficiently than a search engine can.