A new Uncharted is coming, but for Vita again. Not a big miss if it is indeed a card based game. I would imagine it being like Metal Gear Acid.
Multiplatform for such a game would more likely be iOS and Android rather than PS3. It's not a real uncharted game, so putting it on other platforms isn't as big a deal as the game is more about just making money and advertising the Uncharted franchise - of which the actual games can only be played on Sony devices... Sounds like a crappy cash grab to me.