We'll see in an hour. IMO the game has the potential to become a huge franchise this generation, it only needs to be handled right but Sony is stumbling a bit in that regard at the moment, they need to definitely to get their act together until february then the game can be, as you've said, another Uncharted.
A multiplayer component would definitely help further broaden the games' appeal though.
Possible MP for the sequel:
Evolve/L4D style of game mode where one or more players control halfbreeds against a squad of humans
Something like that, or maybe just a Coop campaign (possibly a seperate campaign from the single player campaign, if they don't want to compromise story to allow 4 player Coop) would also help alot. I'm sure there are a bunch of possibilities.