Yes the focus stacking on the RP looks very handy! I’ve thought about a feature like that in the past. I do a bit of product photography so it’d be good for that. Also some studio macro!I missed the touchscreen when I upgraded from the 70D to the 7D Mk. II. I appreciated getting it back when I upgraded to the 5D Mk. IV, but I still prefer the 7D Mk. II thumb switch for toggling between AF area modes over the 5D dual button dance. As such, I would hope that a 7D Mk. III would retain the thumb switch but add a touch screen.
PS - It also wouldn't bother me if it picked up the live-view focus stacking trick from the RP. Kind of a shame that they have not yet retrofit that to the R with a firmware upgrade.