While I do care about the headphone jack, I am mostly bitter about the manufacturers deciding for me that I don't need it. I'd heavily trade off 10% reduction in thickness for a user-replaceable battery and a headphone jack, but it was decided for me that a thinner phone is a big improvement.
There are gaming phones, phones with crazy cameras, and iPhones where the lack of features is a feature. What I wish to have is a phone with as many features and functionality as possible.
That includes (but not limited to): IR blaster Headphone jack MicroSD card slot FM Radio RGB Notification/Status LED
Rather than a slim phone with a glossy finish that will pick up scratches right away unless wrapped in a phone case, the outer cover of the phone should be rugged and replaceable. Like with old Nokia phones. I don't care about few extra grams, or another millimeter of thickness. And I'm sure I'm not the only one.
I was hopeful about the Fairphone at first, but they started removing features as well.