When looking at small sensor technology one should keep in mind that they are plagued with extremely poor angular response (partly due to small pixel size), and we can see now that the new MF sized Sony CMOS still has very poor angular response compared to the larger pixel MF CCDs.
So when they talk about huge improvements in sensitivity on the sides and no need for micro lenses this is in a small format context, it could still mean that angular response is less good than say a 6um Dalsa sensor. Not sure that actually is the case... but I know that for MF sensors angular response is usually around 40 degrees or so, and with sensors for compacts the range used to be like 10 degrees, ie what considered "good" is on a different scale.
Curved sensors open up for interesting lens designs, my guess is that you can simplify optics and improve corner sharpness at the same time.
edit: uhh... mixed it up with RX100, RX2 is 135 full-frame of course. Makes it indeed more interesting. I would still remain a bit skeptical about angular response performance, it will be better compared to the current Sony full-frame sensors, but those don't have good angular response at all, from a tech cam perspective.