Other than for remote sensing and Cumulonimbus avoidance, clouds serve no useful purpose for spacefarers. Unless someone plans to dogfight in the atmosphere, this feature is IMHO not worth the expenditure of time to code and debug. You could add optical depth as another moddable and pluggable callback function, though:
Code:
double clbkOpticalDepth(const OBJHANDLE hBody,
const double Lon,
const double Lat,
const double MJD) const;