I have the SX50 and can say that an extended focal range, beyond the 24-1200, 50X optical zoom of the SX50, is not one of the improvements that the SX50 replacement needs, as I see it.
What it is does need is a wider maximum aperture, a cleaner button layout and ideally a larger sensor. I'm not holding my breath for the larger sensor, but surely a bit wider aperture is doable, as f/3.4 on a tiny sensor is quite limiting. It does a great job when scouting local locations because the zoom can pull in good detail from quite a distance and saves me a lot of walking time, but in low light situations, indoors at night for example, it's a tough go. Granted it is a point and shoot camera that is optimized for outdoors, and it is very good at that, and very few P&S are really good indoors, but a little more attention to low-light situations would expand it's uses nicely. It doesn't have to cut into the S120 territory to be more useful.
The SX50 button layout on the back is frustrating for those with larger hands, and older hands. I've missed shots because the wrong button was accidently brushed against and activated at just the wrong moment. I have DSLRs and other P&Ss and don't have that problem, it's just the SX50.