Hate to bump this thread for risk of giving the impression that there's news, which there's not, it's not happening, but over on a major movie-site forum someone posted this manip:
Pretty much illustrates a huge part of why this shouldn't happen. You need names to sell it, and names by nature aren't what we need for this. And all of those actors, are, you know, oh, in excess of a decade too old. Obviously Lawrence wouldn't be caught dead doing something like this at this stage in her career, but this is what you'd get with a movie: 25 year old Animorphs set in the present day with smartphones and such, with CG animals and a soft-PG13 rating. Hunger Games-lite.
Personally, I'd prefer nothing.