Replacing the mute switch (that allowed you to accurately mute the sound, in the dark, simply by feel) with the Action Button was the biggest iPhone 15 downgrade.
They could rescue that by not only bringing it back, but also keeping the Action Button as an extra button, AND, making the mute switch into a programmable Action Switch, so those that don't use the mute functionality, can give it some other purpose.
E.g. I have a friend who switches his phone on and off from work mode, and sometimes forgets, so this would make it easy for him to check.
Oh, and One More Thing...
Put the on/off button back on top of the phone. Again, renabling easy control of buttons by feel without looking.