Yo, I hurr s'human time.
I guess my first impression was the art style. I'm really disappointed they didn't try anything new; yeah, it would be jarring to kick off with the usual stuff for the pony scenes and then suddenly transition into a new vein of animation, but if they're going to make such a divergent spinoff, I'd kind of like it if they were willing to make some changes to how it was presented. Yes, I know, this goes against the god-tier animation quality we get in the show, but I'd at least respect them a ton for taking the risk, enough to make up for almost any shortcomings in animation, except maybe downright laziness.
I also don't like that they left the humans the same colors as their pony counterparts. It's just cutting corners in my eyes; whereas you could have identified each human with its respective pony through, oh, I don't know, characterization, personality and storytelling, they've just gone and made them the same color with the same hairstyle. I guess I really wanted to see them make the characters actual humans, with skin tones and hair and such, instead of weird, pastel, anime-haired bipeds. It's not like clearly defining races would have any sort of detrimental effect on the show. The opposite, rather, since most of the audience will consist of highly impressionable youths who will see all the people of all different colors getting along and such.
I really want the chance to say, "Oh, such-and-such human character is like a human parallel of Scootaloo, but different in a couple areas," rather than saying, "Oh, such-and-such human character is literally Scootaloo." I want them to introduce us to new characters and let us figure out for ourselves who is supposed to be whom, and then have some humans that have no pony parallels, but are purely invented for this movie.
I probably won't watch it, but that's mostly from a stubbornness on my part, refusing to go to movie theaters at all. But Hasbro can make all the Equestria Girls they want and I won't cry foul, so long as the show stays good and the spinoffs don't have too much (read: almost any) influence on the ponies.