SD card support, 3d touch support and waterproofing seem to be the 3 big add ons for the S7 over the S6. I have the Edge+ and looking to move down to the 5.1" or 5.5" models of the S7.
There's also the 12mp 1/2" sensor with approximately 1.8um pixel size with a F1.7 lense. This should drastically improve low light photography and allow a faster shutter speed in the dark preventing motion blur.
Although they would be good, they wouldn't really affect my usage. I still have 12.7GB free on my 32GB Edge+. Waterproofing would be nice to have, but I've never really wished that I had it since I got it. And if they come up with a good implementation of Force Touch or have waterproofing at all, I'd be surprised.
That camera would be industry leading, I'm sure, but I'm already in love with my current camera, and you know what they say about fixing it and it not being broke.
To be honest, there's a low chance that I'll get a Samsung as my next phone. Not only will there be little novelty, but unless they improve software support, I'll be jumping on HTC (if they're still mainstream at the time) or a Nexus or Moto (it they fix the shortcomings of stock Android)