The camera size is already huge in iPhone 14 Pro that it doesn’t sit well on MagSafe Duo Charger wishing that they figured out a way to at least keep the size to how it currently is but it looks like there’s no getting around it. It looks like it’s gonna be bigger than 45mm Apple Watch at this point.
I actually disagree there. Might be showing why I don’t work in high end product design lol, but I think as a pro model you can go a little crazy on the weight. You can probably save some thickness from under the camera bump somehow if you redistribute whatever can be displaced from under there, which would be easier in a thicker phone. Like any PCB that doesn’t need to be directly under the optoelectronics could be redesigned to go around some of the camera stuff, which would eat into the battery. But that wouldn’t be a problem when the whole thing is a mm or two thicker. 220g is probably not crazy. 250g would be pushing it. 300g would be unreasonable unless they have some real high tech stuff in there to show for it, like some kind of force touch or possibly a 3.5mm headphone connector.
The thing is heavy. I have a heavy case on it as well, go figure. I must admit though, in the past I used to drop my phone on my face. Now I make the split second effort to dodge if I drop it. But the weight makes it feel premium. Sure, the dad test is psychological, but that doesn’t mean it’s not important.
I think switching the back from all-glass to something else would help drop the weight slightly, but at this rate it’s just that there’s so much in these phones. Between the battery, the slabs of glass, the complicated cameras, you’d think fitting a headphone connector wouldn’t be so hard.
If they filled that space with battery, it’d probably be closer to 400g. Batteries are very heavy.
Battery size is obviously a compromise. Apple would have tested larger and smaller batteries, and come to the conclusion that the current size is perfect. They might change their mind, since battery life largely depends on what apps the user runs and trends change over time, but they would’t be far off the mark.
“Something else” would need to be non-conductive (to be compatible with wireless charging) and easily recycled (to meet their environmental commitments). Glass is probably the best option.
Also - glass isn’t as heavy as you seem to think. Plastic is only lighter than glass if it’s really thin, and thin plastic is too bendy. The back has to be stiff enough to stop the phone from bending, otherwise the screen will crack… plastic would be very thick (and very heavy) to achieve that.
The early model iPhones with a plastic back all had steel reinforced plastic backs. Steel is heavier than glass. And it blocks wireless charging.