Yes he's taller. But I'm not sure if this is it. As its rare for tall athletes to run that fast. There's a reason that Randy Moss is a freak.
But even if he takes less strides, this doesn't seem consistent with the running technique of Michael Johnson, where stride length isn't so much where the speed comes from. But it will be interesting to see if the sport starts to move to taller runners (an article I read while posting stated that in the past Bolt was considered to tall, and was told so, partly due to how it was thought to be more difficult for tall runners to get up to speed quickly from the blocks).