It would be nice to be able to pop batteries in and out on the fly, but I suspect that would make it a lot harder to waterproof. I've lost more phones to water damage than I have to battery death.
IMO smartphones peaked around that era, and we've only seen incremental improvements and enshittification ever since. I used to be excited about every new device, but these days all manufacturers are grasping at straws trying to differentiate their rectangular slabs from the competition. AI is the latest gimmick in this trend.