The movie was created very well. It fits the MLP line
well enough that the story line could have worked with
just ponies with a few minor changes. The transformation
to human added a nice twist for it though. Of course
to create the new series too.
It appears Spike is considered more of a pet in the show
since they turned him into a dog. After all they are all
animal characters. Or should I say furry?

It also laid groundwork for Twilight to have a boyfriend. It
will be interesting to see if it works out that way in the
next season. For MLP and Equestrian Girls.
I don't know why there is so much division for the
movie, unless it's just pony purists complaining.