I can't really blame her, I'm bored with Vampires myself.
I was actually getting bored with them before she started writing them, though her "coke and pepsi" take on the modern "sooo goth to be dead" artsy-emo-romantic vampire thing did help to cement my boredom and ensure I probably won't be interested in vampire fiction for at least a decade or so to come at least.
Truthfully though, I'd imagine her claims of being "bored" probably are a marketing gimmick to generate hype for the next book. Get people all invested in begging her to do it, and it will keep the energy going, generate free viral advertisement, etc... such is my suspician.
Honestly though, just because she's bored with Vampires, doesn't mean she'd be interested in going on to do another gothic romance thing with another supernatural creature. To be honest she strikes me as a natural for the "powder puff" sword and sorcery circuit. Or maybe she'll try and get her "Yaoi" on by seeing if she can out-do Mercedes Lackey's "The Last Herald Mage" series.
If she must go the horror route, maybe she won't even do undead. I mean just imagine a re-envisioning of "Creature From The Black Lagoon" except where it's somehow sexy and tragic, and enters the high school swimming pool at night where lonely girls begin to congregate and form a cult in it's honor...
Or given that it's public domain, maybe she'll take the Cthulhu Mythos and turn it into a teen romance. You know, someone about how Hastur stole Cthulhu's boyfriend or whatever and then put her to sleep for a few millenia, only to wake up and go looking to re-win the heart Azathoth the crawling chaos, and engage Hastur (now center of the universe) in the cat fight to end all cat fights (Meow!). Get some human characters involved to hang out in coffee shops so they can chatter with Cthulhu, and exchange fashion advice and stuff and she could call the whole thing "Miskatonic 90210".
Okay enough rambling and picking on poor Stephanie Meyer. Bottom line is, if she's burned out she's burned out. Even if I was a fan (I'm not) it's always a good thing to take a break at that point. She has millions of fans and it's better to stop when your hot and hope you get it back, than disappoint them with something third rate by your standards.