How is the i3 following a 'visionary path'? I lived in Germany for a year and don't remember fun having a different definition over there either.
Design and Concept.
Modern cars have to rethink the usage of class in order to improve visibility. The carbon chassis allows more freedom in design. You can't create an i3 with a conventional steel or alu chassis.
Furthermore you don't need wider tires and high levels of grip to have fun on an open road. A rigid construction with a balanced setup is more important. The i3 felt really responsive,nimble and agile.
One big problem I had with the Model S is the sheer size.