I’m having the same issues after upgrading to Yosemite, but I can use my Intuos after installing the 6.3.13w3 drivers.
Have you had any luck fixing this?
interesting. that is a lot better but there is now a new problem. as I click and hold an object, it slowly gets off center from when the mouse is. So I can now click and drag and object around, but the longer I hold it, the further it gets from where the mouse is actually touching.