One of my favorite actor/wrestler playing one of my favorite heroes? I'm okay with this.
I was really down with him playing Lobo, but he'd make a great Stewart as well.
I'm actually hoping he does play Stewart. He really could revive the GL franchise like he has done with his prior movies.
Some of the reasons people have as to why he shouldn't play GL are kinda baffling. (He's too big, he's not black enough, he will ruin the movie, etc.)