There are more than just external changes here. Instead of the NVIDIA Tegra chip found inside the Microsoft Surface 2, the Surface mini is expected to feature a Qualcomm Snapdragon processor. While many feel that an 8 inch screen is too small for the Office suite to run on, the mini will ship with it included. In addition, the tablet should come with an active digitizer stylus/pen, especially if it is going to focus on its note-taking capabilities.
Microsoft CEO Satya Nadella is expected to handle the hosting duties and we could even see Stephen Elop wearing his Microsoft uniform. Now that the acquisition of Nokia's Devices and Services division by Microsoft has closed, Elop returns to his own stomping grounds. While the answers will probably be revealed on May 20th, at this point we really do not know much about the Surface mini in terms of specs, pricing and availability.
source: MicrosoftNews via WMPoweruser