It is highly unlikely that G16 will have a new sensor.
Usually Canon use the same sensor in the G series for 2 years whether it is new version or not.
G15 is just new and I bet G16 will have only cosmetic change and minor improvements if it comes this year.
Anyway, it is very expensive for what it is and at the moment, the best deal is for sure the G1X. For roughly the same price, you get a big sensor, articulate screen and great Image quality (if you can survive with an ugly camera
The “G2X” may be around the corner but it will be more expensive (according to new Canon price policy, to be good, it HAS to be expensive