The movie was never intended to be a continuation of the original. That fact must never be forgotten. Complaining that the movie isn't the same as the TV series is like complaining that the new shirts for sale at the store aren't identical to all the old shirts in your closet. If you don't like the violence, if you don't like the new character designs, if you don't like the plot of the movie, that's fine. But if the only reason you don't like them is that they aren't the same as they were before, you need to open your mind a bit.
Flexibility is a beautiful thing.
A Girl in Gaia succeeds at what it set out to do. Anime hasn't seen anything like this before, and probably won't see it again for years to come.