Having options in a license can be a reasonable idea, as long as all the options are basically acceptable for the same range of works.
But if we want to recommend the license for manuals, but certain options make the license too restrictive for manuals, that is asking for trouble. If we recommend that license for manuals, people might use it with the options that are unacceptably restrictive, all the while thinking they are following the our recommendation. It is possible to give more detailed recommendations such as "It is ok to use the FOO license as long as you don't use option C or D", but they will be unreliable--people will tend to misremember the details. It is an error-prone system.
