I fully agree with you. I didn't think that Zimmerman was guilty of premedidated murder and malice, however he should be guilty of manslaughter. It was his negligence that caused him to follow Martin, armed, and put himself in the situtation of harm.
He pursued him, Martin confronted him about it, and like a little chicken shit Zimmerman pulled the gun and killed him. If Zimmerman had minded his own business Martin would have continued walking home and would still be alive. Martin was not looking for a fight, but when someone started stalking him, he stood his ground.