NFC and ApplePay
Faster LTE and VoLTE support
LTE carrier aggregation
Bigger battery, longer battery life
Better/Faster CPU
Let me make a couple notes on your reasons.
Faster LTE and VoLTE support - I can guarantee you will probably not notice a difference in speed data usage.
Bigger battery, longer battery life - This actually may be a viable reason, but we will see how the new battery plays out in real life usage.
Better/Faster CPU - Was the iPhone 5s really too slow for you? I mean with a new phone it is expected that the CPU will be faster, but if I have last years 5S I don't think in my head now that's a reason to upgrade, since the 5S doesn't stutter and is not slow in any regard.
My thoughts on Apple Pay: Apple Pay is 95% reliant on stores/restaurants to implement Apple's payment system. People say Android had NFC a long time ago, which is true, but the key is to push stores and restaurants to implement the system so it is ubiquitous enough for us to use the technology.
Now with that said Apple jumping on board with NFC is a
good sign because they will pressure stores/restaurants to implement the new tech, but we probably won't see
most stores implementing it until a few years have passed.
Lastly when I said futureproof I obviously didn't mean we never need to upgrade again. I was just saying since the 64 bit architecture was there we wouldn't feel a need to upgrade for at least 2+ years. And none of the 6 features shouldn't really make anyone jump to get one unless you need a big screen and I understand.
Jumping from a 4s to a 5 was understandable because the 3g to LTE upgrade was like going from 56k internet to cable internet speeds. From 5S to 6 I really fail to see it guys.