Balancing, especially in multiplayer-oriented games, is a tricky thing to get right. Each and every weapon must be taken into account to ensure there isn't one that stands out from the pack with too many strengths.
It's a rock, paper, scissors scenario with weapons speed, power, and other dynamics needing careful attention to ensure no matter what the scenario may be each player has a chance at coming out the victor.
In the old days, when it was just you and your friend sitting side-by-side without a care in the world with a focus on pure fun, balancing wasn't so much of an issue. However, once multi-player advanced into a more competitive spirit if there was a strategy to be exploited, you can be sure it was taken to ensure you came out on top.
These ten weapons became so cripplingly over-powered they ended up dominating their respective games to the point players would be forgiven for giving up and never playing them again without nerfs.
Be it they were given an unfair advantage, crushing damage output, or there was simply no defence against them, they all plagued gamers nightmares due to the frustration generated from their use.
10. Akimbo Model 1887s - Call Of Duty: Modern Warfare 2
The Akimbo Model 1887s effectiveness in online play is mythical throughout the FPS world, and this writer can tell you from experience the legends are 100% true. These relics were the undisputed king in Modern Warfare 2 for a very long time.
Modern Warfare 2, even after various patches, was about as balanced as this writer after only a few pints, but the Model 1887s were on their own plane of overpowered existence. They were essentially high powered shotguns with range damn near close to a sniper rifle, and that is no exaggeration.
This guaranteed a one-hit kill, and didn't require you to go down iron-sights. The sawn-offs were also blisteringly quick to reload as all it took was a flick of your soldier's wrist to re-chamber a shell. If you used the correct perks in combination with them, it made a near-unstoppable killing machine that flew across maps with a full-auto shotgun-rifle.
This weapon was completely broken in Modern Warfare 2's multiplayer for a long time. The great Akimbo 1887 epidemic of those first few months is forever burned into the memories of those who suffered through no matter how hard they may try to suppress it.