This is the end of the trilogy, and Warner is gearing up their reboot of the series. It doesn't matter how the film ended. You can argue that Talia will survive and the son of Batman will be next. But this particular Batman universe is dead - time to move on.
As for dental records, that would be assuming the bodies weren't splattered by the impact, or exploded by the heat of the fire. What is a small hole though, is not finding the wings and engines among the wreckage. Being a remote country, and a covert operation, not much scrutiny would be put on the plane.
I deny the Christ allegory. Christ was put up to public suffering and execution. He also wanted to serve as an example of standing up for your convictions. Batman deliberately put himself in harms way to save a group of people, but he wasn't teaching the people anything in the process, and it wasn't a public execution. His journey was very personal, and his whole motif is rather selfish, as pointed out many times by Alfred.
This was a great film, and is a terrific ending to the storyline. I do wish it would continue, and have serious doubts about the next series of movies.
The little tease of Man of Steel before the movie made me hopeful, though still a bit reserved until more is known.