I don't actually miss much, but I also don't really use my phone a whole lot. I have a smartphone, but it's pretty close to factory settings. I don't really install apps outside Line, I very rarely make calls on it. It probably gets used for transit directions/maps, mail, and Line 90% of the time.

Maybe not a specific feature, but I do dislike the general trend towards large and larger phones/screens. I must prefer the smaller phones we used to have; I know Apple had their smaller phone lines recently but I think they didn't do particularly well.

Aux ports are nice for versatility, even if I was already using wireless earphones. Along with being able to listen to FM right on your phone. It's features I don't use often, but occasionally. I wish the USB-C connector had the option with a clip. IR-blasters were useful and much fun. I never even used the actual remote to manage my LED strip.

I never realized notification lights just kind of stopped existing. But I don't miss them in light of always on displays. Under screen finger print readers is basically a dream come true. Having multiple cameras is nice. OLED screen is an absolute godsend. Overall I'm not unhappy.

SIM card trays for sure.

Squeeze to activate Google Assistant, from the Pixel 2 XL (and maybe others, I don't remember)