I was listening to the MMM (Modern Myth Media) podcast concerning this and they made several valid points. The studio wants badly (BADLY cant be emphasized enough) to jump start the JLA/DCU (Justice League of America/DC Universe) franchise. If they go a direction that does not include the combo of Nolan/Bale then you basically have to reboot Batman yet again in some way, shape or form. The studio could completely botch that since, other than Batman, they've shown no ability whatsoever to do any other character from the DCU any justice at all. MOS (Man of Steel) is getting great word of mouth and, tada, Nolan and his goto story teller David Goyer have their hands all over MOS. If the studio uses the Dark Knight trilogy without Nolan's consent to lead into a Batman/Superman team up film which may include other characters also, they could potentially bastardize the entire Dark Knight trilogy. The best person to bring on to prevent that from happening is Chris Nolan himself and his team. I'm not worried about Batman now as much as I would've been in someone else's care. The attachment of Nolan, Bale, Zach Snyder, and Henry Cavill brings instant credibility to a JLA project and eliminates the need and expense of rebooting the Batman franchise and delaying progress of JLA even further. As has been stated in several articles, this is WB putting their best foot forward, and their best shot at success concerning the DCU.