Being a skilled tactician is not enough to take out 2 mutants of their caliber. Whether you like him or not, Gambit's powers are impressive. Add Sunfire to the equation and a gun and tactics aren't gonna help you much. The healing factor will probably be used as an excuse to bring him back, but I fully expected that anyway. After reviewing X-Men #200, he DOES use his TK, but it doesn't help much. My previous points stand. Cable clearly thought destroying Providence was a better option than fighting them and risking the information there falling into the wrong hands. Whether he could "beat" them in a fight under different circumstances is irrelevant and immaterial. He "lost" because he iniated the self-destruct, not because Gambit and Sunfire incapacitated him.
There is no way that they will kill Gambit. It makes no sense. There is talk that they want to make Wolverine more then one movie, and since they got a "name" actor to play gambit and the rumor is that they payed him a handsome sum of money. so even the legistics in the movie making aspect of it leads on to belive that Gambit will not die so he can come back if they are going to make another movie.