Nex 16mm. Should it have been 19mm or maybe 24mm?

I can understand they wanted a "pancake" or similar to keep the overall camera/lens size as small as possible to satisfy a certain sector of the market.

But really 24mm effective is pretty useless for a general walkabout lens. If it had been 19mm (28mm effective) that would have been much more useable, and only 3mm longer physically. Surely that would have been better?

f/2.8 isn't particularly fast, so the glass (and the overall dimensions) could still have been very compact if they had gone for a 19mm f/2.8 prime.