I just had an amazing idea for Uncharted 3. It could be a God of War inspired mythological quest to uncover the secrets of Pandora's Box or the quest to reach Olympus. You know, some kind of amazing Naughty Dog “Twisted History” story.
Anyway, the finale would see Drake flung into Hades itself, where he has to confront the thousands of mercenaries that he needlessly slaughtered! Suffice to say, it will be a powerful ending.