The 16mm is a write-off. The kit lens reminds me roughly of the quality of Canon's old 18-55mm, so it's middle-road. What they need are new, more expensive primes (expensive because you cannot build a good 16mm "DX" lens and sell it for $250) and some adapters to use existing manual lenses.
I've handled Nex5 with 16mm yesterday. It is pretty nice in manual mode, with known limitation regarding ISO settings. It fits in hand very good, and 16mm is, physically, nice match. I also like 24mm FOV on the camera, but I've taken few snaps (on my card), and although I can not open RAW, only JPG, quality of 16mm is not even near close to pana 20/1.7 (yes, I know it is actually 40 vs 24, but pictures from pana 20 look much much better).
I'm only interested in image quality with legacy glass, since 1,5x is much better than 2x for some of my lenses - for example, leica 35 in M mount becomes normal lens from short telepohoto. If the quality turns good, i can live with all limitations.
Hrvoje