We’re working on adding one for the next major release. Most of the gruntwork is already done, so it shouldn’t take too long to implement.
Currently planned is /CLEAN, /REGISTRY and /STARTUP; which will automatically run the junk cleaner, registry cleaner and startup management tools. These will use the “one-click” implementation of those features currently being tested in SimpleNinja.
CleanSync.exe already supports these arguments: /SYNC, /UPDATE and /LANG; which update the cleaning rules, check for program updates and update the localization files, respectively.
Any other arguments you want to see added?