First of all, Inception may not be a bad movie. The real measure of a movie is whether people like it, whether they feel like their 10$ is well spent. With that measure, it wasn't a good movie to me. I do maintain, however, that Inception is a bad story. Stories are about character, and the characters in Inception suck.
To be fair, Inception is nowhere near the worst movie of the year. One of the largest injustices of all time is that the turd of Alice In Wonderland is one of the 7 movies to make a billion dollars. Hereafter is so tedious, I only stayed in the theater because I assumed that it was building up to something.
Spoiler: Hereafter is like a Ayn Rand book. Reality doesn't support Objectivism or Hereafter's belief in the afterlife, so the author simply creates their own reality, where it's obvious that their belief is correct. This fictional "proof" takes precedence over character, plot, etc. Hence, the "climax" of Hereafter isn't an event of narrative importance, it's an event that shows that the afterlife is real.
Speaking of the afterlife, the reason people see a light when they have a near death experience is just because there's no oxygen going to their brain. It's a repeatable medical condition, not some magical connection to another world. All of these "glimpses of the afterlife" imply that god created a pretty crappy way of separating the alive from the dead.