There are rumors that an official news on the upcoming sequel will be announced by WB and Nolan's camp this January. The source is saying that the longer sequel materializes the less likely Chris Nolan will return. WB will also use Nolan's latest film Inception to spark interest for a Dark Knight Sequel.
Though it is also revealed that Batman 3 is a go with or without Nolan directing. But WB is operating under the assumption that Nolan will return.
I hope Christopher Nolan returns, so that he could finish his opus, then after that I am okay for other directors trying their take on the World's Greatest Detective. - but definitely no to Schumacher!