Don't think that was ever the case - To my knowledge, the CS doesn't parse the command line argument at all. At any rate, here's what the CK accepts:
-OptimizeMasterFile-BuildShaderList-ExportDialogue-GenerateLips-ExportFaceGenData-TagifyMasterfile-ExportText-CompileTextExport-DelocalizeMasterfile-Install
To use them,
- Go to Steam Tools Library
- Right-Click "Creation Kit"
- Properties > Set Launch Options...
- Enter switch name and parameters
- Launch the Creation Kit
At the moment, -GenerateLips is the only documented switch,
To generate LIPs from the command-line, run: CreationKit.exe -GenerateLips:ESMName.ESM
This will load the specified ESM (and any dependent ESMs) and generate LIPs for every dialogue line for which there is a loose WAV file under .../Data/Sound/Voice/ESMName.ESM/…