Excellent director
The guy has a few sub-par films and everyone pretends that they always thought he sucked. It became trendy to hate on him after that Robot Chicken episode with him saying "tweest." Now there is this hive-mind mentality where it is the thought-free response to dislike M Night. A similar thing happened with the movie Titanic. The popularity backlash gives people some reason to feel that they are cool for going against the flow.
The man directs very well.
The only movies that he made that are "bad" are the following:
The Happening: Starts brilliantly but is ultimately sunk by the main characters. Strangely, the supporting cast deliver some excellent performances (I'm no Leguizamo fan but he was great). The story itself is even decent. Plant life developing a defense system against human overcrowding is very cool. Studies had recently revealed that suicides had a particular chemical makeup in their brains not present in other dead people. Connecting the bee die-off, the suicide chemical, and plant defense is a great story idea. Would have been better as a 1 hr Twilight Zone.
Lady in the Water: Based on a fairy tale he made up on the spot to tell his kids as a bedtime story. So knowing this, one can be at least a little forgiving of the very light story. But it wasn't good. This movie is only good for the thing that Night does exceedingly well: characters. The rich line-up of characters are charming. It is like this is the opposite of The Happening. Not a "good" movie but it has enough quality to it to elevate it above your average dumb popcorn flick.
The Last Airbender: To me, this is his only truly awful movie. The source material is a fantastic cartoon series that delivered three perfect seasons. The film loses all of the heart of the original which mystifies me. Night is very very good at "heart." Hard for me to be objective here since the comparison is damning. I really hated this movie.
The rest of his catalog is great. Not flawless but high quality IMO. Night haters are band-wagoners who complain about "twists" but only if they are in his movies.