Honestly the only thing that really hooked me about BW was the story and that's because some of the plot twists were either pretty dramatic or pretty surprising, but that wouldn't be the same the second time round so I'd say it doesn't have much replay value at all tbh. I've tried a few times but never made it past Chargestone Cave, it just isn't that interesting to play again D: Maybe if they included more than just the Unova Pokémon then there'd be more options on what to train and you wouldn't keep seeing the same things popping up again and again and again, but as it stands I really don't find BW very replayable at all.