Nothing like judging a film before you've seen it. Closed minds are the bane of some, unfortunately.
I saw so many so called King fans on other sites saying how rubbish Doctor Sleep was going to be before it was published, all because it was a sequel to a great book.
Wait and see the film before deciding whether it's any good or not, or if this actress playing Carrie was the right choice. They're called actors and actresses for a reason.