The 2007 movie is bad. The CGI looks horrendous (and in a movie that would be immeasurably improved by just showing its monsters way less). The villains are the dumbest, smuggest imaginable stereotypes, while the good guys are utterly flat. The human behavior in general makes no sense (why does everyone keep deferring to the local movie poster painter for everything?). The relationship between Thomas Jane and his son is never really demonstrated, undermining the ending which is the only thing most people actually remember.
The movie's only impressive feature is its ability to bludgeon the audience so hard with its goofy-nihilistic ending that they all forget how badly-handled and shitty the rest of the film was.
So I am actually interested to see if Mike Flanagan can fix this thing up, since it's not a bad premise for a movie.
Just for the hell of it, here's my silly pitch: hide the monsters much more, and give them more of a "Biblical" flavor, so it isn't actually clear which side in the store is right. In the end, our hero tries to convince himself to shoot his own son, but at the last second he can't do it. Then the roof is ripped off the car, and the son is pulled into the air, where he is transformed into a horrifying, deformed Angel-thing before our hero's eyes. Turns out the "religious nuts" were right, and the hero's hardheaded appeal to a materialistic version of rationality is blown to bits. It's the End Times Rapture bay-bee, but it's completely horrifying and a fate worse than death. Cut to credits.