We need another one
I love the Queen, and this movie is a nice continuation. They held out on the scene with Bush. But I would kill to see another sequel about the war in Iraq with the same actors (Blair, his wife, his spin doctor). It doesn't have to attack Bush to alienate some viewer (although I personally do not mind) but it could have just focused on how the public felt Blair lied to them.
If they can get Helen Mirren to reprise her role as the queen and reflect back on the event from the Queen movie (as implied in the Queen's ending) that would be such an awesome way to close the whole thing.
Unless they want another one about how Blair retired.