According to a new report, Microsoft is working with necessary partners to make the advanced features of the Surface Pro digitizer pen avalable, especially when using applications like Adobe Photoshop.
"Surface Pro uses Windows Inbox Drivers and APIs (application programming interfaces) for the Surface pen, which support advanced features such as pressure sensitivity and eraser functionality. There are a number of apps in the Store that leverage these new Windows APIs and can take advantage of all that the Surface pen has to offer. The Surface pen does work with Photoshop, which runs on Surface Pro, though advanced features such as pressure sensitivity and eraser functionality may not be available at this time. Microsoft is working with the necessary partners to make advanced features of the Surface pen available across a number of applications in the near future," Microsoft stated.
Apparently, there is an issue with a driver that prevents pressure sensitivity on the digitizer pen, especially when using Adobe's Photoshop application on the Surface Pro. We may see this update in the next round of Patch Tuesday updates for the Surface Pro.