Be as inclusive as possible
I think that we need to be as inclusive as possible, if only to attract a good number of visitors to the site. If we made it exclusively about literary analysis, the site might quickly fold.
However, being inclusive inevitably raises the question "what constitutes literature?" Everyone will have their own answer to this. If the site becomes flooded with low-value questions, we may decide as a community to exclude certain genres and types of questions. For example, basic questions about science fiction and fantasy works can be migrated to SFF.SE.
One big problem with having too much inclusivity is that it may deter real experts in literary analysis from contributing to the site, especially if they see a lot of questions about graphic novels and manga comics. We may be able to counter this with intelligent (and consistent) tagging. For example, analysis questions about Dickens should be tagged with
charles-dickens. Experts can then zoom in on their own fields. Another draw may be to set plenty of bounties on high-value questions.