Hmmm, it's difficult. You want a complex plot, but you don't like much wars.
Well, Code Geass is the best anime I've seen, and it's got all your wants, but it has mecha (though I don't like mecha and still love it), and lots of wars. The hero gets through because he's amazingly clever, not because he's badass (though, he has a certain superpower), so if you love strategy and intrincate plans you definitely have to give it a try
Death Note is similar, it has a lot of what you asked, and the hero again gets through with brains. And this one's not mecha, and it's much more mystery and not a lot of fighting.
Both have a lot of "oh, shit" moments, and very complex plots, so I can't recommend them enough. By your description, Death Note suits you more than Code Geass, though I liked more Code Geass








