Simplicity and bluntness work just as well--when done right. When not done right, it doesn't. At all.
Usually, if it's extremely complex, it's most likely a mystery, thriller, science fiction, or fantasy. Romance can, too. But usually these are the ones that shine in the department of having many layers and many things to contemplate on--especially mysteries and thrillers. That's what the they strive for. If it's a who-dunnit, you need to be wondering WHO-DUNNIT! And to do that, correctly, means lots and lots of layers.
I write mystery and thrillers so I try my best to make things as hard to figure out as possible. Sure, everyone likes guessing the killer and being right, but when you can guess it from the start, that's no fun. No fun at all.