Honestly, a lot of the best plots move the story sideways instead of trying to retell it. One I keep thinking about was this 'what if' scenario where a former Interpol profiler, who'd been tracking the Kira case from Europe, arrives in Tokyo right as L dies. She's not a genius on their level, but she's got decades of practical experience with serial killers, and she immediately spots all the tiny, weirdly human mistakes Light made that L's pure logic missed. The tension came from her and Light circling each other, with her being this massive, gut-instinct wild card that his perfect, logical plans couldn't account for. It made the cat-and-mouse game feel fresh again.
Another favorite introduced a minor Shinigami who was basically a bureaucrat, disgusted by the mess Ryuk started. This character's power wasn't about killing, but about subtly altering the flow of information—delaying a newspaper by a day, causing a phone call to drop at a crucial moment. The plot became a quiet, supernatural sabotage against Light, forcing him to adapt to chaos he couldn't see or understand. It was less about a direct confrontation and more about watching a meticulously built house of cards wobble from a draft no one else felt.
Those kinds of stories work because they don't try to out-smart the original; they just change the weather in the room, and you get to watch everyone react.