Exactly what the topic title says. Remember, though, the change has to be a relatively minor one. You can't go and say something like "make Uncharted open world", because that would necessitate a full overhaul of the game. Think of this as one minor mechanic added at the last minute to a great game that ruins it.
I'll start:
BLOODBORNE: gets Super Smash Bros. Brawl style tripping. Just randomly. At any time. You may trip. It could be in the middle of a boss battle or a dodge roll or anything. You can't stop it from happening.
BREATH OF THE WILD: Gets map icons and quest markers. These cannot be turned off.
THE WITCHER 3: You cannot use any signs in combat. Use your sword, or nothing.
I'll start:
BLOODBORNE: gets Super Smash Bros. Brawl style tripping. Just randomly. At any time. You may trip. It could be in the middle of a boss battle or a dodge roll or anything. You can't stop it from happening.
BREATH OF THE WILD: Gets map icons and quest markers. These cannot be turned off.
THE WITCHER 3: You cannot use any signs in combat. Use your sword, or nothing.