There are number of layer types which are not supported in Packages (Layer, Map, Mobile, Geoprocessing, ...). I'm forever creating duplicate copies of the same projects: one for editing and authoring, which contains all my reference layers and so one, and a 2nd just for packaging. Typically the only difference between these two for me is that the 2nd has the unsupported layer types removed.
It would be really nice if there was a checkbox for Packaging along the lines of "Omit unsupported layer types" so I'm not managing these duplicates, and back porting changes from the master to the package whenever I discover another typo or need to adjust symbol style.
