Which fighters were very accurate, but did not have the good hand speed that usually comes with accuracy? A person that came to my mind when I thought of this was Mike McCallum. I know he wasn't the slowest person in the world, but he was far from the fastest but he was still able to land his punches clean pretty good.
Alexis Arguello, [a smaller Joe Louis] was deliberate with his punches just as Joe Louis was..Never wasting punches..He, like Louis , used timing and LEVERAGE, to ko their opponents...
Lennox Lewis didn't have what I would call fast hands, but he could still place his punches very well.