If you are planing to install custom panels the user folder has not changed.
/Users/[userName]/Library/Application Support/Adobe/XMP/Custom File Info Panels/4.0/
For custom panels we highly recommend to not use the path to the "standard panels" installed by the application.
My custom panels are showing up in CS6, but not in CC? What needs to change?
in which folder did you place your custom panels? If you use the custom panels folder (see above) nothing has changed from CS6 to CC.
note: please use the XMP forum for XMP related topics: http://forums.adobe.com/community/design_development/xmp_sdk