I guess it would be a tie between
The Evil Within and
Thief, both of which happen to be 2014's lowest scoring triple-a games.
I can't believe TEW is from the same guy who made God Hand, Resi 4 and Vanquish. It's an experience that lacks personality and is filled with seemingly arbitrary design decisions (what an ill-advised stealth system!) that slow the game down. I can't stand the imprecise, clumsy controls. What a charmless game.
The Evil Witihn is basically The Expendables of survival horror. All the tropes are present, but there's no understanding. Gameplay is just a bunch of rehashed horror vignettes. The insta-death scenarios are tedious rather than stressful or exciting.
Thief is a broken, tragic, rewritten mess of a game. High quality art assets can't disguise fundamentally flawed stealth mechanics.
While the city looks gorgeous, its pretty much empty. The sidequests are neat, but most of the time I'm just exploring an vacant apartment; no one's home. If I mess up the lockpicking or set off a trap 9 times out of 10 it doesn't matter since it's empty. All these cool additions to the game are underused. Also, there's so many loading zones! Enter a one room apartment. Pick up a letter opener and a ring. Leave in under 20 seconds. Load for just as much. This content just slows the game down. Then there's a lack of abilities and gadgets. I like Swoop, but it's basically a grounded Blink and the rest of Garrett's abilities are essentially uniquely skinned door-openers.
The sound-mixing is atrocious. The worst I've ever heard in any AAA game. That's not hyperbole. It's broken. Sound cuts out frequently, guards across a courtyard sound like their yelling into the players ear, npcs yell ambient dialogue over Basso repeatedly during cutscenes, and Garrett's voice actor frequently pauses to his read lines. The lip-syncing is horrid. I really miss the sound propagation from the earlier titles. Unless you're walking on glass or water, it's doesn't matter where you walk, Garrett won't make a sound.
Garrett's movement has a nice heft to it. He feels present. But moving through the world is about working out exactly what the designer wants you to do, not using your instincts or experimenting. If a rope arrow is just out of reach, don't bother trying to grab it. You need to look for a crate, or a ladder or a walk way to reach it. It's a discrete puzzle that was made for that specific instance. I wish it was like Assassin's Creed or Mirror's Edge. Instead it's an awkward compromise that isn't very enjoyable. Unlike Dishonored, where the designers have a set of rules that you can rely upon, Thief is about instances. These guards will patrol in this pattern no matter what. This object can be leaned around, while another identical object cannot. You can climb this crate, but not this one.
Both are major disappointments considering the respective teams past work.