First off, no, \[ will never be implemented. Currently \ is not special and implementing that proposal would require that it become special which would require that \\ become \ (otherwise what you write when you want \[ to appear?), which would break some existing nodes. But beyond that, what we don't need, IMHO, is more special characters than the current set of <, &, and [. I'm not even happy with the current specialness of | in node linking.

One or more of the &yadda; forms will probably be implemented eventually. Though I personally find <code> and &#91; adequate.

The handling of [ ] happens very late in the PM page processing. This was surprising to me and some of the existing PM code seems to indicate that this either wasn't always true, always planned, or always expected. I fixed one bug associated with it by making the default HTML escaping also escape [ and ]. That is why you can now use those characters in several fields of user settings including using <code> tags in your signature.

This also fixed the problem with preview munging [ ] in subject lines. But it appears that preview turns &#91; into [ and that the final submit then strips the [. I'll have to look into that.

        - tye (but my friends call me "Tye")