Shyamalan - Why this?

Rating: Null/10 (5 February 2017)

SPLIT - M NIGHT SHYAMALAN - The Real Deal
The movie is about a man suffering from a disorder of multiple personalities. He abducts 3 girls to whom he manifests his various personas while warning and scaring them of The Beast, his most extreme, yet to come, personality. His psychiatrist tries to help him while investigating his activities.
Now for the real deal, M Night Shyamalan disappoints. That's the word. Disappoints.
He could have improvised a bit by hooking the audience to some concrete aspects of the story. Why does the antagonist abduct the girls? And the specific ones at that? While James McEvoy makes an honest attempt at the character or characters, M could have infused a bit of logic into the scheme of things. I felt that the 3 girls could have beat the guy to a pulp any time. The action sequence I mean? The generation is real smart these days!
Where is the dread? Where is the scare? I was hoping to add something of an underrated version of Sidney Sheldon's "Tell Me Your Dreams" to the elite club of multiple personality concept, but M disappointed.
Why can't the thinking of characters be realistic?