This is suddenly taking a turn towards Skyfall vs Casino Royale.

I'll elaborate just a tad.

First off; what Bullet said. Casino Royale had a pretty weird and off-putting ending, for a Bond movie. Sure, it's nice to step away from the tried and true formula, but then doesn't Skyfall fit that perfectly?
Instead of Bond Single-handedly(or alongside a femme fatale) assaulting the villains fortress, figuring out his plan and then offing him, the roles are switched, with Silva attacking Bond's "Fortress". Sure, Skyfall(the estate, not the film) isn't a fortress, but it lures Silva away from the populated areas, leaving only Bond and M for the remaining potential death toll.

Also