BIG NO. I don't like her, in general. To have her play Buffy would make me want to stake myself.
If I could cast anyone in this movie (assuming they're using the same characters as the original film), here's who would be on my list.
Buffy - Kristen Bell, Dianna Agron, Adrianne Palicki, Mary Elizabeth Winstead, Emma Bell, Ellen Page, Katie Cassidy, Rachel McAdams, Emma Watson
Pike - I actually can't decide on anyone for this. It's too easy to just list the guys from Supernatural. Let's move on and not do that.
Merrick - JP Manoux, Ralph Fiennes, Hugo Weaving, John Cusack... and because my DH suggested it.... Tommy Lee Jones. Or, if you like the irony? Christian Slater. Why not? It could be fun.
And since I'm probably not shutting up about this movie anytime soon, here's my DNW list.
Buffy - Megan Fox, Miley Cyrus, Lindsay Lohan, Paris Hilton, Britney Spears, Christina Aguilera, Kristen Stewart, Dakota Fanning, Reese Witherspoon, Emily Osment, Selena Gomez, Demi Lovato
Pike - Chad Michael Murray, any guy that's been a main cast member on a Disney channel show, Michael Cera (I just can't see him in this role)
Merrick - Judd Nelson, Matt Dillon, Keanu Reeves