For the reasons listed here, overview questions need to be highly focused. In particular, they need to be more focused than if you asking about a single denomination.
For example, take the question "What should or shouldn't people do on the Sabbath?" While this would be on-topic if talking about a specific denomination, it would likely be problematic as an overview question.
In particular, it would be hard to answer in depth for each denomination what the answer is, since for overview questions, all the denominations need to be put into a single answer (see Can part of a question be answered for overview questions?). This obviously precludes going into detail for each denomination.
What I propose for questions like this is a "list of questions" question.
They would similarly to wikipedia list articles. Instead of asking "What should or shouldn't people do on the Sabbath?", you would ask "What questions are there about "What should or shouldn't people do on the Sabbath?" from the point of view of different denominations?" Then, there would be a single community wiki answer, listing questions from this site answering that question. Since all the links are in one answer, voting doesn't become a "popularity contest".
Each of these questions can then go in depth about the beliefs of the denomination in question. Then some starting at the "list" question, can click the links, and see the views of the different denominations.
This can serve to organize questions that already exist in a way that tags can't (since we obviously can't make a tag for each overview question).
If you all think its a good idea, I can make a trial question of this form.