Some wikimedia projects (Wikisource) would largely benefit from a method to
partially protect the text of an article.
A new syntax would delimit protected sections, e.g. <protect>protected
text</protect>, or maybe <div class="protected">. Protected text may be edited
only by sysops. Other parts of the text may be edited by anybody.
No modification of the edit window is required in order to implement this. If a
user who is not allowed tries to edit a protected section, he will simply
receive an error message when he submits his text, (or something similar to what
one gets in case of edit conflict).
Needless to say, unpriviledged users should not be allowed to add new <protect>
tags to articles.