Or maybe they feel like pulling a MGS2. None of you will know what happened, but basically the creator figured he'd swap out the main man Snake, the guy who built the series with an anti-Snake called Raiden. Everyone hated it.
There were many ways of looking at it through, because the creator was a genius. I saw it as a better look at Snake. You got to see how much of a hero he had really become by viewing him in a second person perspective from Raiden, a total rookie with no idea what he was doing.
So to realte this to Uncharted: I think it would be cool to play as this new guy and run alongside Drake, to be able to really get a good idea of what sort of person Drake really is. I mean he's a mass-murder with a real attitude. Some love him and others don't.
But on the other hand we've always seen him as a sort of realistic Ratchet, so maybe seeing darker sides to his character might piss people off, and take away the Uncharted feel and charm.