I'm rereading the manga at the moment (got it in the humble bundle a couple of weeks back
), and I can recognise most/all of the characters in the trailer but it looks like they're probably mixing it around in terms of the basic story and making some significant changes.
Not necessarily going to be a bad thing, as most source materials need to be changed in some way to fit onto the big screen, if just because films tend to require you to cover the story faster than a book, or appeal to a wider audience and do the introduction a bit faster.
What I don't particularly like are the overly large eyes which feels like it's playing up to the old anime stereotype unnecessarily, especially as in the manga and anime her eyes were nowhere near as out of proportion as they appear in the trailer.
I'll definitely be going to watch it at the cinema even if my normal movie group don't, as I'm willing to give it a go and it's a film I've been waiting to see for years (if just in the hope the anime gets re licenced and re released in hd).