9. Needlessly Including Motion Controls
With the enormous success of the Wii in the mid-2000s, motion controls were the newest industry trend, making gaming significantly more accessible for casual players, and therefore opening up the potential consumer market to a far larger audience.
Catering to a more casual demographic was all well and good when it came to pedaling simplistic party games, but the popularity of the Wii had the unintended effect of seeing motion controls included in a series of new releases around the same time where they just weren't needed.
Instead of simply pressing a combination of buttons to stop a murderous Nazi shoving a knife in your chest on Call of Duty 3, you literally had to wave your PS3 remote around like a lunatic, which was just totally unnecessary.
The issue wasn't motion controls themselves, but more the ham-fisted implementation in games that didn't need them solely to follow the trend. Though the PlayStation Move and Xbox Kinect were not resounding successes, at least including motion controls in those systems made sense.