The Japanese site Mapcamera interviewed Sony.
1) Currently, Sony has no plan to implement 4K internal recording on the A7s. However they recognize there is a huge request to get this feature in future cameras.
2) Sony is planning for making a new mark II A-mount lenses to replace old popular lenses i.e. 70-300, 24-70, 16-35. More to come in the future
3) Sony is still quite young in terms of mirrorless market, they think of themselves as a challenger, but because they are a challenger, they believe they can do a lot of innovative stuff.