I watched the first episode of Sherlock (for the first time), and there's a really obvious comparison here between Sherlock on the one hand and L from Death Note on the other. And it's a beautiful illustration because one show does everything right and the other does everything wrong. Sherlock is clearly designed to be way more OP than L, his deduction skills are just far past the scale – but in every other respect, he's a total idiot, who makes fairly obvious mistakes and whom anyone could just walk up to and shoot if ever he became a serious problem. L on the other hand never does any one particular thing which seems superhuman, but he consistently, reliably makes good decisions and accurate deductions.
Like, one show is what happens if someone who isn't that smart herself tries to write a highly intelligent detective, and the other is what happens if someone who actually is smart tries the same thing. And this is like a recurring problem, too. Whenever people try to write characters far smarter than themselves, they just end up being super good at that one thing but it doesn't transfer into general decisionmaking. It's like a caricature of what intelligence is.