All I want is fewer stupid characters. Perfect example: Dom in GoW2. Essentially, he decides to go off on his own personal mission and potentially leave the planet at stake for what? The most pointless side character ever; his wife.
(Yes I know she was supposed to make the big burly metal tank man seem more human, but Epic failed...well, epically there. Nice try, though.)
What the hell was his plan once he found her? Was he going to carry her through gunfights? Was he going to make her hide while he and Marcus did the fighting? Come on, man! She's not even wearing armor! You're miles underground, you're in the middle of the enemy compound, your own safety isn't even assured, and you're somehow going to get you, your partner, and your wife out in one piece?! Thoughts, man. Think them.
Games that claim to be SCARY and FRIGHTENING aren't. Take FEAR, for example. Call me desensitized, but out of all her appearances in the entire series, Alma has only scared me twice; at the ladder in the first one, and at the start in the armored car in the second one. Developers seem to be all to willing to take the easy way out and go for shock scares instead of making a genuinely scary game. All I'm asking for here is a little atmosphere. For example, it looks downright silly today, but I still get creeped out playing The 7th Guest. Sure the live-action cutscenes are cheesy beyond all hope, sure, the graphics aren't cutting edge in the least, but damn it if they didn't make a creepy game. A lot of it had to do with the subtle little things like weird paintings you'd find around the house, and the appropriately creepy soundtrack that would pick up in the right places and make you jump at nothing. That's the kind of scary I want to see instead of this maybe-vaguely-frightening-the-first-time-jumpy-scares.
Anything that Halo did to truly innovate the FPS genre, such as recharging shields, two weapon carrying capacity, and to some degree, even the control scheme has become groan-inducing, simply because of the number of imitators. Sure, it worked beautifully for Halo, but with developers trying to make the format fit their games, (Goldeneye: Whichever One it Was That Killed Bond in the Dumbest Manner Possible comes to mind) I've simply wished to see an FPS where you can't dual-wield, you can carry an entire armory easily, and left trigger doesn't throw grenades.
As for nitpicky-type stuff, the word "campaign" as used to describe the story mode of a game has always bothered be for some undiscernable reason.