But what was causing the problem in the first place? Was it a hardware or software issue? On a hunch I went to Wacoms' website and browsed their legacy drivers. See, the night before I had downloaded the latest software for my Intuos4. When troubleshooting it's important think back to what you changed last. I had, more or less, eliminated Photoshop from the list of culprits, and Wacoms' drivers had certainly given me trouble in the past. With that in mind I downloaded and installed driver version 6.3.10w2. Lo and behold it seems to have worked! Photoshop is operating as it should and I still have access to Wacoms' cloud service.
Win-win!