The Blades are greedy and paranoid. In Oblivion they treated Martin, essentially a Dragonborn, like a god. And now it seems that they half the respect and loyalty they used to have. Not quoted word for word, but they basically tell you if you don't kill Paarthanax we don't want anything to do with you. So much for protection from the "Dragonguard".
The Dark Brotherhood are just a band of cut throats with little to none discipline and honor in what they do. Again in Oblivion they treated Sithis and the Blood Flower(Night Mother) like they were God and Jesus. And when the corpse of the Blood Flower gets to the Sanctuary, there like "eh, whatev's".
With this, The Dominion, the fall of the Empire, no more Septims, and the Civil War, it just seems like TES is heading further into a dark part of history. Think that was the goal? Opinions would be great.