I personally do not think so:
- the advances for the iPhone 8 (primarily the OLED screen and perhaps wireless charging might only be available on this model ) will probably only exist for a single cycle to celebrate the 10th anniversary
- next year all phones should have the OLED screen and wireless charging
BUT... and this is just speculation... going OLED edge to edge on a phone the size of the current 7+ would allow them to sneak a "mini apple pencil" into the body. (The rumored iPhone Pro) And they'd probably make it capacitive so they wouldn't need a battery in it like the pencil in the iPad pro. (I know some of you will immediately begin flaming against the horror of a stylus and how they'd never do that, but remember Steve Jobs is no longer calling with us. His disdain for the need of a stylus is legendary as well as large screens and tablets, but we now have large screens, ipads and the apple pencil.)
While this is all possible, it's not expected to happen.
The real question is what they do with the line-up next year. If they make this year a preparation for next years revamped line-up, then we may see the OLED 5.8" iPhone 8's successor have "normal" features, with the 6.4" OLED iPhone Plus becoming a "Pro" device, adding a pencil, etc.
Once again, not rumored or expected, but possible.
I think the more likely outcome is that they keep what they're doing now, just add the larger plus model to the OLED lineup next year, and discontinue the 7S form factor next year.