I used a 7 Plus over two years. Had the XR camera camera worked the same way, I would have bought it but it was pinch-zoom.
The XR display was nice and the portrait mode, though not quite the same, is pretty good.
The issue is not dual-lens vs single-lens but the way that Apple adjusts the framing. The dual lets you touch a dot and slide—why won’t Apple let the single do that or make it a preference? Yea, the touch does shift from one lens to the other but that’s not necessary as the slide to frame works either way. The point is that touch-slide can be done with your thumb while holding the phone with the same hand. Pinch-zoom can’t—you need two hands or must put it in your lap to frame the shot if doing it one-handed. Or have only one working hand.
I have large hands so the 7 Plus, while awkward, was workable for me. The XS is smaller which makes it better. The 7 Plus has been converted to a iPod with truly decent battery life.
Had Apple offered the X at a nice discount when the XS was offered, I might have considered it. They didn’t and there were some performance and storage enhancements for the same price so...
I expect the XS to last me till 5G is a thing. Had I bought an XR, I’d expect the same thing. 2021 perhaps or 2022? I can wait.
I’ve seen the rumors that the next iPhone (XI?) may have 3 lenses or whatnot. Ehhhh... I’ll hold out for 5G.