coming from a 6pro into the 8pro, the differences are certainly less clear than they ever have been in the past when making a jump from a device 2 years old to a brand new device.
however, the differences are there, and in my opinion, worth it.
for anyone needing to use their phone as a mobile hotspot, you know with the 6pro (or at least my 6pro) you were getting what felt like maybe DSL speeds through the hotspot connection. the 8pro has amazing speed for hotspot tether and is good enough for doing work on the go where you maybe don't trust the coffee shop network you'd have to connect through otherwise.
the screen is a huge upgrade, flat, bright, amazing.
the camera upgrades are worthy.
either which way you go, sticking with the 6pro, or upgrading to the 8pro, having less differences between devices is a good thing. it means the market is maturing to a point where you don't feel compelled to upgrade every cycle.