Why are reviewers putting so much emphasis on story rather than gameplay/replayability?

[-Ack!-]

Because (let's face it) gameplay has been pretty much perfected or at least there is a formula for amazing gameplay in every genre, so story and style are the only things that set games of the same genre apart. The only way to screw up gameplay is to either be terrible at game development in general, or to try something new and fail at it.