Wait, how is this first generation? Do you consider any refresh of an existing line to be "first generation"? What would you consider not to be "first generation".
As an example, Apple had been making white iBooks for a long time before their Intel transition. But the 1st gen MacBook used a different white plastic that could absorb oils from your hands and turn a nice shade of orange/brown. http://appleinsider.com/articles/06/07/26/apple_recognizes_w...
With a brand new design, you risk problems like that slipping through the cracks. Maybe it turns out that the new keyboard mechanism starts missing presses once the usual crud falls in between the keys, or maybe the USB-C connector isn't durable enough and stops charging reliably a few months in. If the new models have any issues like that, waiting for the second version would save you some headaches.