Due to organic nature of SE sites, both in their genesis and usage, there are and there will always be cases where there are sites that overlap in their subjects.
Classical example are all of older sites - stackoverflow, serverfault, superuser and their offspring e.g. drupal. In these cases it is fairly simple to determine where does a question really belong - the subjects are well delineated (though borderline cases can still occur).
Looking at EL&U the relatives are: literature (will soon become beta) and writers (active). These sometimes overlap in their subjects and will probably continue to do so in a way that is different from stackoverflow and superuser.
This raises two questions, one general and the other specific to this question:
What should be the attitude towards ambiguous questions? Should such questions be left to see if they get good answers or immediately referred to other site?
The question I referred to is one of questions tagged with a tag rhetoric. The problem is that although rhetoric deals with effective use of language in general, the names of figures (see the right pane here) are mostly known from analysis of literature (poetry and prose) and are perceived as specific for those subjects.
I am biased towards keeping rhetorics in EL&U, though have no objections to take it wherever it belongs - the primary goal here is to lower the discussion noise by making the rules easier to follow.