The Synchrodyne by itself is capable of a great deal, containing several modules in one, prepatched internally to create a vibrant range of sounds. It was difficult to cut many of the control capabilities from the Synchrodyne to keep it within the scope of an analog switched-capacitor filter module. The expand lets us bring many of the little nuances of the Synchrodyne to the patchable world.
It is designed to be powerful and extremely dynamic when minimally patched, but when patch cords start flying around to be open and experimental. You may also use many of the parts of the Synchrodyne and Expand separately in various parts of your patches. The open architecture allows it to do many jobs, even small ones.