That would only matter for the release version, for testing/personal mods it would not matter as much. If creating official content is faster it might be worth adding the ability to create an explicit test module that uses the same process as official content but it goes to a test directory and can then be selected instead of the official content (or just have a directory for test content that can be used as an alternate for the official content without actually overwriting the official content). This would be better for people who are just experimenting.
The switch between loading official content and test content could easily be done as a command line parameter. Then it would just be a matter of switching file paths to look in (unless the parameter IS the alternate file path to use with the official content being loaded when it is not present).
Also one way to reduce publishing time would be to have a(n optional) file that stores the relationships from the last successful build so that only the changes would need to be checked. This is done by most commercial compilers (with incremental compiling / linking), and while it is likely to be difficult to implement reduced times would ultimately be helpful when creating more official content for the later years / additional DLC. Depending on how robust it is, this could even allow for it to be stopped and resumed later.