I thought the ending was refreshing. My only real complaint with the movie is that you don't really feel the gravity of his character's sudden loss of hope.
Despite this, I enjoyed it. Cliches and all.
Up until the he sees his wife dead in the window, he's the strong group leader who is trying to get people out of the mist. The movie doesn't really give us time to appreciate the moment where his wife is dead and he snaps. That, and the CGI monsters really sapped a lot of the dread the mist itself played in the movie. The meat of the movie is Thomas Jane and friends VS the nutbars in the super market. The mist stopped beng scary the first time I saw that first digital tentacle.
Despite this, I enjoyed it. Cliches and all.