just ran into this exact issue with ps cc 2014 and windows 8.1 .
the strange thing is that everything was working fine until one night I toggled windows ink on/off in the Wacom driver and the sensitivity broke and looks like ill have to apply the fix above. unless a windows update changed something.
To Adobe: If this is to be the default going forward for Windows 8 systems and CC can you PLEASE talk to Microsoft and get them to implement a SIMPLE ONE CLICK method of removing all pen feedback in windows. This now makes the great and simple Wacom driver checkbox "use windows ink" kinda usless if we are to abide by this new default. And will need you to work with Microsoft to get a proper solution so we don't have to deal with registry fixes and gpedit.msc changes that don't really solve all the issues.
no ripple.. no right click and hold hover etc etc..