Except for the part about having too much gore, I completely disagree with you. It does falter a bit when it tries to switch between comedy and action modes as the plot to kill Kim Jong Un unravels. But it still works well as a satire of our celebrity obsessed media culture.
James Franco plays his character perfectly. (Granted his character is the sort of smug, smarmy asshole which is not a huge stretch from Franco's current media image.) Kim is more than just a caricature here. He is portrayed as a charismatic master manipulator with breathtaking daddy issues. A lot of the movie looks cheap and fake but even that very fakeness starts to make sense when you see just how far Kim is willing to go to make his "worker's paradise" seem real.
So while this movie may not work for film aficionados who only like the kind cinematic masterpieces put out the Herzogs, Kurosawas, and Michael Bays of this world it is funny and watchable. Obviously if Seth Rogan and James Franco give you a huge hate boner, this is not the film for you. But if you usually like their work, you'll enjoy this movie too.