No one went to prison. Bush served out two terms (the first one unelected, but that's an entirely different question). The US occupied Iraq for 9 years. If this is the "accountability" you're touting, it's frankly pathetic.
> Practicing democracy isn't always fast nor is it perfect, but it does work.
That's a major understatement, in the case of the US. The US killed hundreds of thousands of people in Iraq, in an illegal war of aggression, justified to the public on the basis of outright lies, with the complicity of much of the established media.
> the CIA is subject to more congressional oversight, for example
The CIA, on orders from the Bush administration, carried out a global torture program, in which it kidnapped people off the street, including in Europe, and smuggled them off to black sites for torture. The Obama administration decided not to prosecute anyone. In Obama's words, "We tortured some folks," but we have to leave the past behind us. When there was eventually a Senate investigation, the CIA spied on the Senators involved. When that came to light, the CIA apologized, but no one in a position of responsibility faced any serious consequences. The same goes for when the CIA destroyed evidence of torture - no consequences.
> They're banned from using blacksites and the CIA is no longer allowed to hold foreign nationals for extended periods without representation
That's very reassuring. I'm sure the CIA has mended its ways and is now staffed and led by boyscouts. They wouldn't do anything like, say, plan to assassinate or kidnap Julian Assange out of an embassy in London.