Nothing in the mobile industry is really future proof. With the rumors of a 4k display, expanded VR, HDR Amoled Tech, for the S8? A person can argue that a 1080p is yesteryear tech.
To me, if you can get a phone with a processor that will be good enough (A9, A10) for 2 yrs, tons of software updates, get major apps, and doesn't have major bugs, you have a device that is good for awhile. Apple does that even if the spec wars go to Android devices.
What I want in the iPhone 8 is 4 or 6gb RAM (doubt on 6, but 4 is realistic), QHD AMOLED Tech, End to End Display, Quick Charge, Wireless Charging, and whatever else Apple can add in there. Technically 3D is still "future tech" since not many companies offer that with their devices. So I could see 3D Touch being more useful in iOS 11/iPhone 8.
if they add back the headphone port, I'd buy the iPhone8 as you described in a jiffy