You are giving Buffy way too much credit. It's a great show, is extremely well-written, and has inspired hundreds of academics, but saying it revolutionized storytelling and character dynamics just isn't true. Neither serialization nor strong characterization was a new concept, and stating that most popular TV -- which, so far as I know, is dominated by American Idol, episodic sitcoms, and episodic procedurals like CSI, NCIS, and Law & Order -- wouldn't be what it is right now just wrong.

As to Twilight, you admit you're not a fan, and outright dismiss it, so how can you say for certain who it's touched, and what its significance will be in a decade hence. I'm not saying it's going to outlast Buffy, or is artistically superior, but waving it away right now sounds like nothing more than a Trekkie saying Lucas is a hack, and Star Wars will never mean anything.