If you did want to change the AppData location go to the command prompt and type regedit. Then go to HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Explorer>UserShellFolders
Right click LocalAppData and click modify. Assuming you want to change the location to another HDD make a folder on there called AppData and copy the location, i.e E:\AppData. In the Value data box change it to the new AppData folder location you just copied and press OK. Move the Activision folder from the old AppData folder on your C drive into the new one.
This is for Windows 7/Vista, I assume it would be the same for Windows 8 too. Let me know if it works, if it doesn't I can try to help.
- Peeque