Sub 5" screen, 3.5mm jack, removable battery, 2-stage camera shutter button.

My old Sony Xperia XZ1 Compact had all of those, except for the removable battery.

I had a Google pixel 3a which had squeeze sensors, with lineageOS I had it assigned to my flashlight which was super handy. Also I enjoyed the heart-rate sensor on my GS5. Also really liked the DAC in my LGV20.

Removable battery is #1. My old Galaxy S3 (not even my first phone-yes I'm old) has absolutely godawful battery life but I had I think 4 total batteries around to make sure I could always have it even on a heavy use day. That sucked, but at least it was doable with a really easy process (peel off plastic back, pull out and swap battery, snap the backplate back on).

I keep an old phone around and sometimes use it to play like a video for my cats to watch if they're laying on my bed when I'm not in there. But it has to stay plugged in because it loses the first 20% in about 15 minutes.

And that phone in particular (a pixel 2) is particularly a pain to replace the battery in the first place.

I miss the days when everything wasn't glued together. The biggest hurdle to battery replacement or screen replacement is all that damn glue.

My HTC ChaCha had a full qwerty keyboard. Now I'm lucky if the on-screen one bothers to show up in some apps.

I might be the only one, but KEYBOARDS!

I even designed my own keyboard attachment to get one back.

Wish it was ranked choice voting. For me the list is: removable battery, expandable storage, ir blaster, headphone jack. I think repairablity is the most important and i never use the headphone jack but do use ir sometimes so thats the only reason its last. On phones with oled screens notification light is a software feature and fm requires the headphone jack.

My Motorola Moto Z had a shake shake flashlight feature. Not sure if this was Android or Motorola but it was very useful.

3 way tie between 3.5mm jack, easily removable, and now that microSD Express is finally becoming mainstream, a microSD Express card slot. It'd be nice to see in a flagship or at least a Mediatek mid range chip like the dimensity 8400

I know they dont all remove it, but man audio jack phones were awesome. My usbc adapter sucks and bluetooth is spotty and low res.

I miss controlling the volume on a per app basis. It gets unwieldy, but it was nice sometimes.

I bought a modern off brand with an audio jack and micro SD, because why would I spend 3 times more for less features?

Physical keyboard

Human coded Smart Keyboard. Ever since they changed to learning algorithms the spelling and grammar corrections have gotten much worse.

Samsung had a little pressure sensitive area at the bottom of phone screens in the S9 era. It was handy and I had it set up like a hidden home button.

The S9 also had a variable aperture camera, which I feel like could have been developed a lot more.

I also miss notification LEDs. Sure, AOD mostly replaces it, but it was fun setting different colors for people, situations, etc

The Essential phone had a ceramic back that was very comfortable and cool in the hand. Though it was slippery. Another idea that could have been developed further.

The different back materials on the Moto X were very satisfying. The customization of that phone was unmatched!

I think this is a One UI 7 thing, but the battery indicator for connected Bluetooth devices has completely disappeared. The only way to check the remaining battery life of my connected headphones or speakers is through a third party application, I can no longer find a way to do it in the OS itself.

Yes, that one right there in the picture.