Some things were already mentioned so here my other pet peeves:
customizable difficulty - no default preset will be as good as one that can be modified to your liking. Sometimes the issue lies with difficulty making things more of a chore than a challenge, sometimes they tune things too much where you get stuck in a weird middle ground where one difficulty is way too easy and the other bashes your teeth in.
character speed control on PC - we had this stuff figured out in 2002, when Splinter Cell came out! Why the hell are we still stuck with terribly slow walk and slightly too fast jogging? This isn't hard to implement either - there are already multiple speed states when playing with a gamepad, all that's required is an option to control it with a keybind.
visible body in first person games - I always try to immerse myself as much as possible and having a physical body helps sell the idea that I'm a character in this world rather than just a floating camera.