The last Dragonborn did not kill Miraak. Hermaeus Mora did. Even that sorcerer guy said the last Dragonborn would be the "Second strongest to ever live".
Someone has to be more critical in the reviews, or did you not like a review I left for you? Personally, I think some of the reviews try to sugarcoat to much, I'm incapable of doing that without sounding fake. Since the last time I've been told I give ones out too easily, I've changed to giving it to games I want either deleted or unpublished and fixed.