Two, he's a manhunter. He's pro-active rather than reactive. He goes after the bad guys rather than wait for them to come to him. Ostrander said Martian Manhunter will be super-heroic in nature and tied to the character's involvement with the Justice League. The connection has to be there and honored.
New villains are in store for the series.
MM needs his own rogues gallery. We'll have a smattering of old villains as well, but our principal thrust is the new villains. The series will be edited by Peter Tomasi. J'onn must bring the full array of his powers to bear in an extraordinary investigation that brings him face to face with the spirits of her dead wife and daughter.