It's always been my opinion that Kevin Smith is a very good writer, and not a very good director. His style pretty much consists of setting a camera down and shooting actors reciting is sometimes witty, often hilarious dialogue. Smith seems to be an odd choice to direct an action film, even if that film is a comedy. The results prove this, as Smith's style just doesn't jibe with Cop Out.
This movie had all of the ingredients to be good. Willis, even in bad movies, is always fun to watch. Morgan is extremely funny, and I'll watch anything he does, if only to see what surprises he has up his sleeve. The story has enough weird twists to satisfy my wacky side. Putting all of this together should have turned out a lot better than this. Smith usually puts his film-geek knowledge into his dialogue. Here, he's forced to direct the gags put forth by Robb and Mark Cullen. But I'll repeat what I said earlier: Smith is not a director. So the film ends up being a mish-mash of different styles that just doesn't mold into a movie.
The main issue here is that, in the 16 years since Clerks was released, Smith has, more or less, made the same movie over and over again. He never showed any signs that he was interested in branching out, and it served him well. Here's hoping in the future he sticks to what he knows best.