It is definitely an upgrade. Even cropping to 5x you’re still going to have a 26% larger sensor area plus increased resolution you can take advantage of with enough light (or fancy ML algorithms).
I am really disappointed they didn’t accomplish an ACTUAL 4 lens system where the telephoto zooms from 4x to 8x within the periscope build. I was thinking that was their answer to four lens competitors while keeping the 3 lens look. Everything is there, giant “plateau” for the room, folded lens for the necessary length. Thought they might pull something similar on the Air as well with some 18mm equivalent to 32mm magic.
I’m sure they’re looking into it and it might even be they built the style for it in the event they manage to accomplish it during this design’s run, even if they do never actually achieve it, like getting Face ID thin enough for the MacBook notch.
2nm for power efficiency to shrink the battery again and gain the needed space, variable aperture for the lens performance at two focal lengths. Probably need to figure out how to make it so it’s shock resistant enough is the other missing piece.