Structure
Formatting issues are well known in the context of word processors. You won't define the template for business letters for your customers on a letter-by-letter basis. While the formatting may support the content, creating a specialized version does not rectify the investment.
It makes sense to have a common structure for specific types of documents. It is easier to deal with meeting minutes if they have the same basic structure. The same goes with decisions, use cases, user characters, and so on. An individual structure of a document may support the content better as a generic one. So if the gain is big in relation to the investment, authors need the freedom to do so. But keep in mind that readers have an easier time if similar content is presented in a similar structure.
A stylesheet and a template to covers the best practices to structure a given type of document supports authors to provide their information for the documentation more quickly. The template works also as guiding tool to reference aspects that have been relevant for the team in the past. It must not be required to fill out the template completely! Authors are encouraged to provided information only for those parts of the template that do actually apply.